.P8 H24 
Copy 1 



A Study, by the Crop Survey Method, of 

Factors Influencing the Yield 

of Potatoes 



A THESIS 

PRESKNTED TO THE FACUIvTY OF THE GRADUATE SCHOOIv OF 

CORNELL UNIVERSITY FOR THE DEGREE OF 

DOCTOR OF PHILOSOPHY 



BY 

EARLE VOLCART HARDENBURG 



Published as Memoir 57 
Cornell University Agricultural Experiment Station, June 1922. 



A Study, by the Crop Survey Method, of 

nfluencing t 

of Potatoes 



Factors Influencing the Yield 



A THESIS 

PRRSRNTRD TO THK FACUIvTV OF THK GRADUATE SCHOOL OF 

CORNEIvIv UNIVERSITY FOR THE DEGREE OF 

DOCTOR OF PHILOSOPHY 



BY 

EARLE VOLCART HARDENBURG 



Published as Memoir 57 
Cornell University Agricultural Experiment Station, June 1922. 



^8 M a4 






.1^ 



3 

CONTENTS 

PAGE 

The crop survey as a method of research 1145 

Biometry as apphed to crop-survey data 1147 

fO The taking cf records 1147 

Description of regions surveyed 1148 

QJ^ Long Island 1149 

Steuben County 1153 

IVIonroe County 1154 

Frankhn and CHnton Counties 1155 

]\Iethod of studying survey data 1156 

The study of factors 1157 

CHmate 1157 

Elevation 1159 

Crop rotation 1 162 

Value of land 1166 

Soil 1169 

Plowing .' 1171 

Time of plowing 1171 

Depth of plowing ? 1173 

Manure and fertihzer 1177 

Home-mixed fertilizers 1179 

Quantity and value of fertilizer 1180 

Manure and fertilizer used in the four regions 1182 

Analysis of fertihzer 1188 

Method of appljang fertihzer 1191 

Use and influence of hme on potato land 1196 

Adaptation and yield of varieties 1197 

Source of seed 1205 

Sun-sprouting of seed 1208 

Chemical treatment of seed 1210 

Interval between cutting and planting 1211 

Dusting cut seed 1214 

Type of seed 1215 

Large as compared with small tubers for seed 1215 

Whole as compared with cut seed 1216 

Large as compared with small seed pieces 1217 

Number of eyes 1220 

Types of seed used in the four regions surveyed 1221 

Relation of amount of seed to yield 1224 

Date of planting 1231 

Hand as compared with machine planting 1232 

Checkrow as compared with drill planting 1234 

Depth of planting 1237 

Depth of cultivation 1242 

Ridge as compared with level culture 1244 

Frequency of cultivation 1246 

Spraying 1255 

Relation of date of harvest to yield 1263 

^Method of harvesting in the four regions surveyed 1265 

Types of storage in the four regions surveyed 1269 

Length of storage period 1269 

Summary 1270 

Conclusions ."■.... 1272 

Author's acknowledgment . 1273 

Bibliography 1274 

Survey blaiJk 1280 

1139 



A STUDY, BY THE CROP SURVEY METHOD, OF FACTORS 
INFLUENCING THE YIELD OF POTATOES 



A STUDY, BY THE CROP SURVEY METHOD, OF FACTORS 
INFLUENCING THE YIELD OF POTATOES ^ 

Earle V. Hardenburg 

Almost from the date of their estabHshment, practically all state and 
federal experiment stations in this country, as well as many foreign 
stations, have tested, by diverse methods, the relative influences of factors 
affecting the yield of potatoes. A review of the abundant literature of 
the subject shows that a majority of these tests concern the influence of 
seed and fertilizers on yield. This fact, further substantiated by the 
results of the study herein reported, indicates that, with the exception of 
climate and soil, seed and fertilizers are the most vital factors affect- 
ing yield. Because of the widely differing environmental conditions under 
which the tests have been conducted, it is possible in only a limited degree 
to draw definite conclusions from a summary of the results. Furthermore, 
a large part of the literature fails to supply much detailed information 
as to the methods used in the experiments, and gives little if any considera- 
tion to factors affecting yield other than the one principally concerned 
in the respective tests. This means that most of the evidence available 
to date is of only limited application. 

A comparison of the conclusions reached and the recommendations 
made by experiment stations, with those warranted by actual practice as 
found on farms in a potato-growing region, is therefore of considerable 
value. Such a comparison is, to some extent, made possible by the 
use of the survey method of collecting and studying data on the influ- 
ences affecting the yield of potatoes. The survey method has accordingly 
been applied to the study of such factors in several potato sections of 
New York, and the results ^re herein compared with those obtained 
experimentally. As an additional check on the conclusion's drawn, 
the biometrical method as applied by Rietz and Smith (1910)- has 
also been used in studying those factors which, according to the sur- 
vey method, appear to affect the yield to the greatest extent. The survey 
method of studying crop production, wholly aside from the agricultural 
methods involved, has proved to be a most valuable means of determining 
the actual practice thruout the State, and has aided in correcting many 
false ideas of long standing concerning cultural methods used with this 
crop. 

The collection of data was begun in the smiimer of 1913 and continued 
thru the summer of 1914. In 1913, 330 records of the 1912 potato crop 
were taken from as many potato farms on Long Island, and 360 records 

' Also presented to the Faculty of the Graduate School of Cornell University, February, 1919, as a major 
thesis in partial fulfillment of the requirements for the degree of doctor of philosophy. 
= Dates in parenthesis refer to Bibliography, page 1274. 

1143 



1144 



Earle V. Hardenburg 



of the same year's crop were obtained from that number of farms in 
northern Steuben County. In 1914, 300 records were similarly taken for 
the 1913 crop in Monroe County, and 300 in Franklin and Clinton Counties 
combined. This gives a total of 1290 records for the crops of 1912 and 
1913. Each record was in the form of a filled-out survey blank, a 
sample of which is included at the end of this paper, and was as complete 
as possible in the details listed. Because of the similarity of regional 
conditions and of cultural practices, the counties surveyed were studied 




Fig. 125. regions included in the potato 

SURVEY 



as^four distinct sections, as follows: (1) Long Island, including the potato- 
growing areas of Suffolk and Nassau Counties; (2) Steuben County; (3) 
Monroe County; (4) Franklin and Clinton Counties. The location of 
these areas is shown in figure 125. These regions were selected, not 
because they include the counties of highest total production, but because 
they represent typical and distinct centers of potato production in the 
State. 

The importance of potato production in a region is probably best 
indicated by figures showing the percentage of total crop acres devoted 
to this crop and the average potato acreage per farm. A summarj^ of 



A Study of Factors Influencing the Yield of Potatoes 1145 



the scope of the survey and the status of the industry during the years 
1912 and 1913 is given in table 1. Of the four regions surveyed, the 
potato crop is regarded as of most importance on Long Island and of least 
importance in Franklin and Clinton Counties. 

TABLE 1. Summary of the Four Regions Surveyed 







Number 


Acreage 
surveyed 


Average 
size of 


Per 

cent of 

total 

acreage 


Per 

cent of 

crop 
acreage 


Per 
cent of 

crop 
acreage 


.\verage 
potato 
acreage 


Average 
yield 
per 
acre 


Region 


Year 


of 
records 


farm 
surveyed 


potatoes, 


potatoes. 


m 
notatoes, 
for the 


per 
farm 


for 
farms 












farms 
sur- 
veyed 


farms 
sur- 
veyed 


county 
(1909 
census) 


veyed 


veved 
(bushels) 


Long Island, in- 




















cluding parts of 




















Suffolk and 




















Nassau Coun- 




















ties 


1912 


330 


8,188.16 


65.0 


37 


44 


23.0 


24.8 


175.5 


Steuben County. . 


1912 


360 


5,301.10 


145.8 


10 


18 


8.3 


14.7 


136.4 


Monroe County . . 


1913 


300 


3,728.25 


112.1 


11 




8.0 


12.4 


126.2 


Franklin and Clin- 




















ton Counties. . . 


1913 


300 


2,160.00 


169.5 


4 


10 


5.7 


7.2 


179.3 



THE CROP SURVEY AS A METHOD OF RESEARCH ^ 

From its inception in this country, agricultural teaching has depended 
largeh^ on textbooks, collateral references, and the published results of 
experiments. There is still a considerable lack of practical information 
which can be supplied only by protracted experimentation or by the 
study of large numbers of survey records in the regions concerned. Fre- 
quently problems arise which local experiments fail to solve because of 
the impossibility of handling the work on a sufficiently extensive scale. 
Large numbers of records might very often be the means of discovering 
the common causal factor prevailing thruout a region, thus furnishing the 
solution of the problem or at least a working basis for its solution. A 
typical illustration of this is furnished in the investigations on pecan 
rosette by McMurran (1919). Pathologists had previously been unable 
to account for the cause or to recommend measures for the control of 
this disease, which w^as so prevalent thruout the pecan orchards of the 
Southern States. McMurran, by taking records of many orchards in 
the various pecan regions of the South, discovered that the disease was 
almost entirely absent in the orchards of the rich river bottom- ands, 
and from this observation he deduced that the cause of the disease laj^ in 
certain soil deficiencies. 

The farm-crops survey aims first of all to search out the actual facts 
concerned in the production of a given crop in a given area. This informa- 
tion, obtained in sufficient quantity, may then be regarded as statistics 



1146 Earle V. Hardenburg 

from which to determine the most beneficial influences and practices. 
The survey idea was first launched in New York by Dr. L. H. Bailey, 
under whose direction horticultural studies were made thruout the State. 
In 1903 Professor John Craig started an orchard survey campaign in west- 
ern New York. Such of these surveys as were completed have been 
published as Cornell bulletins (Warren, 1905, a and b; Cummings. 1909; 
Martin, 1911). Under the direction of Dr. G. F. Warren, the survey idea 
was extended to include the farm as a whole, with the result that whole 
farming areas, with the farm as a unit, have been studied in what are 
called farm-management surveys. The results of such studies have also 
been published as Cornell bulletins (Warren and Livermore, 1911; 
Thompson, 1915). Montgomery (1913), in discussing crop surveys, states 
that their primary function is to determine how to grow the crop, while 
farm-management surveys aim to determine when to grow the crop. 
Warren (1914) attests the value of agricultural surveys by saying that there 
are many kinds of agricultural information that can be found onlj- by 
svirvey methods, since the conditions in question exist only on the farms. 
He states further that agricultural knowledge, to be of most value, 
should be the result of both survey studies and experimental tests. 

The accuracy of survey methods depends very largely on such factors 
as the personality of the man procuring the records, the manner in which 
questions are asked, the number of records obtained for each region studied, 
the unit used as a basis in the study of a factor, accuracy in tabulation, 
and the final interpretation of results. The more extensive the record to 
be obtained, the greater is the number of records necessary for final 
accuracy. The principal faults in much of the survey work to date lie 
in the attempt to include too much detail and in the use of too few records. 
Warren (1914) is of the opinion that ordinarily 1000 records should be 
used, tho 500 may be enough in some eases. However, the necessity of 
such large numbers depends somewhat upon the scope of the survey. 
By the law of averages, large numbers tend to eliminate individual errors. 
Spillman (1917) has said that the accuracy of any average depends on three 
things: first, on freedom from bias; secondly, on the number of items from 
which an average is obtained; and thirdly, on the accuracy of the individual 
items averaged. Considering the limitations of much of the experimental 
evidence to date, large numbers of survey records are undoubtedly pro- 
ductive of as nearly accurate results as are obtained by experimental 
work. As emphasized by Warren (1914), the region siu'veyed should be 
an agricultural, not a political, unit. Furthermore, the records should be 
taken only during a normal year unless records are to be obtained for con- 
secutive years. Unfortunately for this study, the year 1912 was at first 
drier than normal, but the abundant rain which fell late in the growing 
season caused some blight rot; 1913, however, was a more nearly normal 
year. 



A Study of Factors Influencing the Yield of Potatoes 1147 

BIOMETRY AS APPLIED TO CROP-SURVEY DATA 
Biometry as a science is beginning to have wide application, wherever 
sufficient data make its apphcation possible, in the solution of problems 
involving the study of the interrelation of factors or the study of cause 
and effect. Until the present time, biometry has been used mainly only 
in the study of inheritance and in the correlation of characters in large popu- 
lations of plants and animals. Its use has been thus limited because only in 
such studies have conditions been so controlled that none but the factor or 
factors under observation could affect the results, and because it has been 
possible to use large numbers of individuals for such investigations. 
Biometry should have a place in the study of crop-survey data wherever 
large numbers of records are involved, in order that the coefficient of 
correlation may serve as a check on the conclusions otherwise drawn and 
that it may furnish, thru its frequency table, a description of the prevailing 
practice in the region in question. 

Tolley (1917) states that the coefficient of net correlation affords a 
good means of determining the net effect of each of several factors bearing 
on a result, or of eliminating the effect of other factors when it is desired 
to find the true relationship between any two. Applying biometrical 
methods to farm-survey data on fattening baby beef, Tolley has shown 
how the gross apparent correlation between any two or more factors may 
be substituted in a derived formula and the net correlation of any two 
factors thereby deduced. 

A biometrical analysis of some of the more influential factors involved in 
this study has been made, altho, owing to the relatively large numbers of 
records used in each study, only the gross correlation has been computed. 
Aside from the actual significance of the coefficients obtained, much 
information of descriptive value relative to the frequency of a given 
practice may be foinid in the frequency distribution tables. One of 
the chief functions of biometry is description. It affords a means of 
classif^ang a group of individuals not possible by any other means. 

THE TAKING OF RECORDS 

Five men constituted the party employed in the taking of records in 
1913. This made it possible for four of the party to travel thru the 
potato regions in pairs while the fifth man copied and checked each clay's 
records. In this way, any discrepancies in the records could be checked 
up by a return visit to the grower or by discussion within the party. The 
data on the 1913 crop were taken in 1914 by two men. 

As previously noted (Spillman, 1917), the value and accuracy of survey 
data depend largely on freedom from bias. This may well apply to the 
selection of farms to be observed. Therefore it was decided that for these 
surveys the only lunitation in the selection of a farm was to be in the 
acreage of the crop produced the previous year. This limitation was set 



1148 



Earle V. Hardenburg 



at a minimum of 5 acres, tho a very few records were taken on farms 
having a production area of only 4 acres. The reason for the establish- 
ment of this minimum limit lies in the assumption that growers of acreages 
smaller than 5 are probably not growing potatoes in a manner comparable 
to the average of the region. The data on cost of production, tho obtained 
at the same time and indicated on the survey blank, are not a part of this 
study. The subject of cost has been studied by Fox (1919), formerly of 
the Department of Farm Management at Cornell Universit3^ 

DESCRIPTION OF REGIONS SURVEYED 

For a better understanding of the environmental conditions under 
which the potato crop was produced, a brief description of climate, soil, 
topography, elevation, length of growing season, market facilities, type 
of farming, land values, and status of potato production, is given for each 
of the four regions surveyed. Unfortunately, of the regions concerned, 
only Monroe and Clinton Counties have been soil-surveyed by the United 
States Department of Agriculture. More detailed knowledge as to these 
environmental influences may be obtained from figures 126 to 129. 




Fig. 126. elevations of the regions surveyed 



A Study of Factors Influencing the Yield of Potatoes 1149 



LONG ISLAND 

Most of the potato crop in Suffolk County is grown east of Riverhead 
on both the north and the south shores of Long Island. The Long Island 
Railroad furnishes the transportation facilities for practically all of the 
surplus crop of this region. Most of the roads are improved to a high 
degree. Thus the time required for shipments to reach New York City 
need not be over one day and no delay is necessitated by transfers to 
other railroads. 




Fig. 127. growing-season rainfall (in inches) 
in regions surveyed 



Nearly all of the crop in Nassau County is grown north of a line drawn 
east and west thru the central part of the county. Most of the surplus 
crop of this county is transported directly, in heavy wagons and motor 
trucks, to the Wallabout and Harlem Markets in Brooklyn. 

The greater part of Long Island is of marine deposit formation, the 
elevation ranging from a point at about sea level, in the Hampton section, 
to an altitude of nearly 300 feet in some places on the north shore. The 
average elevation of the potato fields surveyed was 65.5 feet. Due to 
the low elevation of the south shore, the crop is exposed to heavy sea fogs 
which make conditions favorable to the development of late blight. The 



1150 



Earle V. Hardenburg 



topography is in general fairly level, tho the slightly rolling lands along 
the north shore gradually rise until they merge into prominent hills along 
the Sound. 

The potato sections of Long Island show an average growing-season rain- 
fall of from 16 to 20 inches, which is somewhat higher than that of most of 
the potato sections of New York. Rainfall seldom limits production here. 
The tempering influence of the Atlantic Ocean affords a growing season of 
approximately 200 days between killing frosts, which is greater than that 




Fig. 128. 



LENGTH OF GROWING SEASON (iN DAYs) 
IN REGIONS SURVEYED 



of any other section of New York. The growing season on Long Island 
is fully a month earlier than that in the other three regions under dis- 
cussion. 

The soil of most of the potato-growing areas of Long Island is of a sandy 
texture, topped by silty loam in layers of varying thickness. This is 
counter to a rather common impression that the Long Island crop is pro- 
duced in sandy soil. The greater part of the central section of the island 
does consist of sand, and this supports little vegetation aside from scrub 
oak and pine. That the potatoes are grown mainly on the Sassafras 
series of soil is shown in figure 129. 



A Study of Factors Influencing the Yield of Potatoes 1151 




1152 



Earle V. Hardenburg 



The importance of the crop on Long Island is shown by the fact that no 
regular system of crop rotation is practiced, potatoes being grown for 
several successive years on the same land. In order to maintain the 
humus content, cover crops of rye are turned under each spring. The 
coimnonest practice is two to four years of potatoes, the land being cover- 
cropped to rye over winter. Along the north shore, where a rotation 
is sometimes used, wheat seeded to clover and timothy follows potatoes, 
the hay being grown from one to two years before the sod is plowed for 
corn, cabbage, and cauliflower. Potatoes then follow these cultivated 




Fig. 130. harvesting irish cobbi.kk- i\ nassau county in july 
The large immature vines should be noted 



crops. Wheat and hay are the principal rotation crops on the southern 
shore. 

Much double-cropping is practiced in Nassau County, the early potatoes 
being harvested in July and the second crop in late August and early Sep- 
tember. Land producing a first crop of potatoes is commonly planted to 
turnips, beets, carrots, or other root crops, or is set to cabbage for the fall 
market. Rye is used here also as a cover crop. A field in which Cobblers 
were harvested one day and turnips were planted the next day, is shown 
in figure 130. 



A Study of Factors Influencing the Yield of Potatoes 1153 

Land values are higher on L6np; Island than in the other potato sections, 
partly because much of the land in Nassau County is held for real-estate 
purposes and partly bec^ause of its geographical advantages and adapt- 
ability for potato production. The values range from $100 an acre in 
Suffolk County, to $1000 an acre, real-estate value, in Nassau County. 

The average size of the farms surveyed was 65 acres, of which 37 per cent 
was in potatoes. On the average, 44 per cent of the total crop acreage 
was in potatoes, while the average potato acreage per farm was 24.8. 
The potato crop is relatively more important in the farming system here 
than elsewhere among the regions surveyed. 

The number of records taken on Long Island was 330, representing a 
total of 8188.16 acres planted to potatoes in 1912. The average yield 
per acre, on the farms surveyed, was 175.5 bushels. 

STEUBEN COUNTY 

The area of most intensive production in Steuben County lies in its 
northeastern part, along the Cohocton River valley and in the hill sections 
on each side. The Delaware, Lackawanna & Western and the Erie Rail- 
road handle the potato shipments. Local buyers take most of the crop 
from the grower, buying it either at harvest time or on contract. They 
store it in temporary warehouses along the railroads or ship it direct. 
Because of the unevenness of topography and the heavy nature of the 
soil in this county, the highways are often so poor that the movement of 
the crop from field or cellar to the shipping point is seriously handicapped. 
For this reason, most of the crop is moved at the times when the 
roads are in the best condition. Much of it is shipped to New York 
and Philadelphia, but the variety Spalding's Rose 4 is sent to Florida 
as seed. 

The elevation of the surveyed fields ranged from 1200 to 2100 feet, the 
average being 1659.2 feet. This wide range in elevation has considerable 
influence on the development of the potato crop, as is indicated by this 
study. A large part of the total crop is produced on hillsides of varying 
slope, the incline often being so steep as to limit the use of heavy machinery; 
on the other hand, many of the best potato fields are found on the level 
table-lands at the highest elevations. 

Northern Steuben County has an average growing-season rainfall of 
from 16 to 18 inches, which is sufficient for maximum crops. Because of 
the heavy nature of the soil, years of abnormally large rainfall often cause 
much loss from blight rot. The growing season between killing frosts 
averages 150 days, and is usually sufficient to mature the crop. Because 
of better air drainage and cooler average temperatures, the crop is often 
later and the yields are larger on the farms at the higher elevatio'iis. This 
was not the case in 1912, however, as is shown later in the discussion of the 
influence of elevation. 



1154 Earle V. Hardenburg 

Five soil scries are principally concerned in the area studied in Steuben 
County, as shown by figure 129. Nearly half of the crop of 1912 was grown 
on Lordstown silt loam, which gave a higher average yield than any other 
series. In elevation this soil series is next to the Volusia series, which is 
found only at the highest elevations. Tho both of these soil series are 
naturally low in fertility, the highest average yield was obtained on the 
Lordstown series, while the lowest average yield was produced on the 
Volusia series. The soils on the hilltops are largely derived from .shale and 
sandstone; the valley soils, altho naturally higher in fertility, contain 
more stone and gravel. 

Relatively long and fixed rotations are used in Steuben County, the com- 
monest being potatoes, oats, hay two years. Frequently the sod is left 
until long past its profitable stage for hay, with the result that the humus 
content remaining for the potato crop to follow is seriously depleted. 
Farms on which the sod was left down for the shortest period of years 
showed the highest yield, and vice versa. Sometimes wheat followed 
oats in the rotation, giving two successive years of grain. The wheat was 
used as the nurse crop. These farms showed .a higher average yield of 
potatoes than did the farms using only one year of grain. This may have 
been due to the additional residual fertilizer left from the second year of 
grain, or possibly to production on better soil than is ordinarily devoted 
to potatoes. Buckwheat, in which Steuben Countj^ ranks second according 
to the United States census of 1909, is commonly used to follow old sod 
land that is being broken for potatoes or to break virgin land recently 
cleared. On the smaller potato farms, corn for grain or silage is grown in 
the rotation with potatoes. 

Land values are as low in Steuben County as anywhere in New York, 
for much of the land is infertile and rough, and little of it has been sold 
or rented in recent years. The estimated values ranged from $25 to $80 
and more an acre, the average being about $50. The average size of the 
farms surveyed was 145.8 acres, 10 per cent of this being in potatoes. The 
per cent of total crop acres per farm in potatoes was 18. The average 
yield per acre on the 360 farms surveyed, which represented a total of 
5301.1 acres of potatoes, was 136.4 bushels, 

MONROE COUNTY 

The potato section of Monroe County covers most of the region east, 
west, and south of Rochester. Potatoes are an important crop on most 
of the farms south of the fruit belt that extends across the northern border 
of the county abutting on Lake Ontario. Excellent railroad facilities pro- 
vide transportation for the marketing of the crop, loading stations being 
located on the New York Central, the Lehigh Valley, the Delaware, 
Lackawanna & Western, the Erie, and the Buffalo, Rochester, & Pittsburg 
Railroad. 



A Study of Factors Influencing the Yield of Potatoes 1155 

Elevation is not an influential factor in this region, since its variation 
is only between 400 and 1000 feet, the average being 592.5 feet. In general 
the topography is gently rolling, and in only a very few places is it suffi- 
ciently uneven to affect production or the usual cultural practices. 

The growing-season rainfall is somewhat less than that of the other 
regions, ranging normally from 14 to 16 inches. However, it is seldom 
insufficient for maximum production. Due to the tempering influence of 
Lake Ontario, the average growing season is 165 days, which is somewhat 
longer than that of the other regions except Long Island. 

The soils on which the potato crop is produced are principally of the 
Dunkirk and Ontario series, as shown in figure 129. Altho both of these 
soils are naturally fairly fertile, a study of comparative yields shows that, 
other things being equal, the Dunkirk soils gave the higher production. 
The soil map of Monroe. County shows an especially wide range in soil 
types within each of these series. 

The cropping system of this region is usually a four-years rotation of 
potatoes and grain or another crop, oats, wheat, hay. Corn is most 
commonly chosen as the additional cultivated crop to be raised with 
potatoes, tho beans and cabbage are sometimes used. The value of potato 
land ranged from $50 to $250 an acre, the average acre value being $150. 
The farms surveyed averaged 112.07 acres in size, 11 per cent of the total 
acreage being in potatoes; and the importance of the crop is emphasized 
by the fact that 15 per cent of the crop acreage is in potatoes. The average 
yield per acre of the 1913 crop, for the 3728.25 acres of potatoes on the 
300 farms, was 126.2 bushels. 

FRANKLIN AND CLINTON COUNTIES 

The areas of production in Franklin and Clinton Counties are two : one 
consists of a broad, level stretch of fertile valley land along the St. Law- 
rence River, extending across the northern end of Franklin County and 
over into Clinton County; the other consists of hill and valley farms 
on each side of the Saranac River, in central Clinton County. In both these 
areas the potato lands extend back into the foothills of the Adirondack 
Mountains. Most of the production centers in Franklin County are located 
along the Rutland Railroad, while the Delaware and Hudson Railroad 
handles most of the crop of Clinton County. The greater part of the sur- 
plus is marketed in the eastern seaboard markets after the early crops of 
Long Island, New Jersey, and the South have been sold. A thriving 
trade in seed potatoes has been developed with Long Island, New Jersey, 
and southern points. 

Being in close proximity to the Adirondack Mountains, this region has 
a wide range in elevation. It varies from 300 to 1850 feet, the^average 
for the farms survej^ed being 1038.2 feet. The excellent yields obtained 
at the higher altitudes are due largely to the cool climate there alTorded. 



1156 Earle V. Hardenburg 

In spite of the range in elevation, very little of the crop is produced on 
anything but level land. The farms along the St. Lawrence River valley 
are generally level or gently sloping toward the river, and most of the crop 
in Clinton County is also grown on fairly level fields, either in the Saranac 
River valley or on top of the foothills of the Adirondacks. 

Due to the northerly latitude of this region the growing season is rela- 
tively short, the average period between killing frosts being 150 days. 
Elevation and latitude are jointly contributing factors for an ideal potato 
chmate conducive to late maturity of the crop. As a rule the growth is 
stopped by frost, resulting in a crop more or less innnature at harvest 
time. This gives a product of excellent seed value and keeping qualities. 
The growing-season rainfall averages from 14 to 18 inches, the mountain 
areas receiving the greater precipitation. The rainfall is uniform thruout 
the growing season, each month averaging 3 or more inches. 

Most of the soils of this region are a fine sandy loam and are included 
in the Ontario, Caloma, and Terrace soil series. The Ontario series com- 
prises the area along the St. Lawrence River, and the Caloma and Terrace 
soils comprise most of the area in central Clinton County (fig. 129) . The 
Ontario series is largely of sedimentary origin and its fertility is rather 
higher than the average; while the Caloma and Terrace soils are mainly 
of glacial drift formation and are of only mediocre fertility. 

The commonest system of cropping is a five-years rotation of potatoes 
and corn, oats, ^hay three years. The corn is used mainly for silage. 
Hops have been regarded as a relatively important cultivated crop in the 
Franklin County area until recently, when low prices, disease, and com- 
petition with the western crop caused a decided decrease in acreage. At 
present, potatoes are the chief source of cash income in this district. Land 
values here are similar to those in Steuben County, the range being from 
$10 to $100 an acre, with the average at about $50. 

The average size of the farms surveyed was 169.5 acres. Only 4 per 
cent of the total acreage, and 10 per cent of the crop acreage, was in 
potatoes. The average yield per acre on the 300 farms surveyed, repre- 
senting 2160 acres, was 179.3 bushels. 

METHOD OF STUDYING SURVEY DATA 

As previously pointed out, one of the handicaps in any effort to de- 
termine, by an analysis of survey data, the absolute influence of a single 
factor on yield, lies in the difficulty of separating the influence of other 
factors from that of the one in question. This is a necessary step, how- 
ever, in insuring accuracy and a correct interpretation of results. A 
preliminary study of factors influencing potato yield in Steuben County 
in 1912 (Hardenburg, 1915 b) indicated that the most important factors 
were the amount of seed used per acre, the value of manure and fertilizer 
employed per acre, and the frequency of bordeaux spraying. The results 



A Study of Factors Influencing the Yield of Potatoes 1157 

of the present study have borne out that conclusion. Therefore, in con- 
sidering the influence of a given factor on yield, an effort has been made 
to eliminate as far as possible, or at least to give due credit to, other con- 
tributing factors. 

Since the study of each region concerns but a single year, too definite 
conclusions must not be drawn in interpreting the data presented. De- 
pending upon the normahty of the season in which the crop was grown, 
the degree of influence of a given factor may or may not be maintained 
under average conditions. Tho cultural practices are not usually varied 
radically from one year to another, differences in the length of the grow- 
ing season, in the average growing-season temperature, and in rainfall, 
tend to affect the influence of those practices. Therefore it will not be 
possible to answer, in any appreciable degree, many of the questions 
that will be raised. The consideration of experimental results is there- 
fore of value in furnishing background for the study of «ach factor. As 
stated by Warren (1914), there are questions that can be answered only 
by a study of the results obtained on farms, and other questions that can 
be answered only by the results of experiments. 

Little attempt has been made to discuss any potato literature except 
that pertaining to seed, fertilizers, and planting, these being obviously 
the most influential factors under the grower's control. In reviewing the 
literature, one is impressed by the large quantity available and by the 
meagerness and unreliability of the data given to substantiate the state- 
ments, 

THE STUDY OF FACTORS 

CLIMATE 

A brief review of climatic conditions in each of the surveyed areas has 
been given, not because of any definite influence on the crop under con- 
sideration, but to make clearer the normal conditions to which the crop 
is subject. Facilities for taking weather data in each of these regions 
are not yet sufficient to allow of any attempt at the correlation of rainfall 
and temperature with yield for a given year. 

In general, the average growing-season temperature to which the crop 
is subject has a marked influence on the vitahty of that crop as used for 
seed. Briefly, high temperatures tend, to produce devitalization. Long 
Island growers obtain average yields ranging from 150 to 250 bushels per 
acre from new Maine seed, but the use of the same stock for seed a second 
year results in greatly inferior yields, as is indicated in figure 131. The 
same principle is demonstrated in the rather common practice of introduc- 
ing seed from northerly latitudes, a practice which is justified on the basis 
of better yields, as is shown in the tests cited under the caption Source 
of seed. 



1158 Earle V. Hardenburg 




Fig. 131. growth variation between new and one-year-old maine seed stock on 

LONG island 
The photograph .shows also the characteristic topography of potato lands in Suffolk County 

Valuable studies of the influence of, weather on the yiekl of potatoes 
in Ohio for a period of fifty-five years have been made by Smith (1915), 
and a similar study for a period of twenty-six years has been made in 
New York by Fox (1916). The relationship of both growing-season 
rainfall and temperature, in both States, is expressed in terms of the 
coefficient of correlation (r). A comparison of these coefficients shows 
that .July is by far the most critical month with respect to these factors, 
in both Ohio and New York. The coefficient of correlation between tem- 
perature and yield is in most cases negative for both States, indicating 
that yield is inversely proportional to increase in temperature. So far 
as rainfall is concerned, the correlation for Ohio is positive and fairly 
large, indicating that rainfall is ordinarily a limiting factor in yield. The 
correlation of rainfall and jdeld in New York, on the other hand, is negative, _ 
showing that years of high rainfall are years of low yield. The average 
growing-season rainfall for the potato sections of New York, previously 
given as ranging from 14 to 20 inches, is evidently sufficient for this crop. 
The negative coefficient of correlation is probably a reflection of the fact 
that years of highest rainfall in New York have been years of severe loss 
from blight rot. 



A Study of Factors Influencing the Yield of Potatoes 1159 

ELEVATION 

Elevation as a factor influencing production has been determined from 
the figures shown on the topographic sheets of the surveyed areas pub- 
Hshed by the United States Geological Survey. As far as possible, the 
location of the potato fields for which data were taken was indicated on 
these topographic sheets at the time of taking the data. The chief 
difficulty in determining the absolute influence of elevation lies in the 
fact that ■ increase or decrease in ek^vation is usually accompanied by a 
difference- in soil type. A study of elevation, therefore, really involved 
also the consideration of both climate and soil. The writer is not aware 
that any test has ever been made in which either one or the other of these 
factors was studied with the other factor eliminated. 

Progressive increases in altitude and in latitude are similar in that each 
is accompanied by a reduction in temperature. T^e United States 
Weather Bureau, in computing temperature equivalents, makes use of the 
principle that every 300 feet rise in altitude is accompanied by a reduc- 
tion in temperature of one Fahrenheit degree. 

Influence of elevation on Long Island 

Elevation cannot be considered a potent factor in the Long Island area, 
for its highest point does not greatly exceed 200 feet. Many farms along 
the south shore of Suffolk County are below sea level, the sand dunes 
alone keeping out the sea. A typical Long Island potato field is shown 
in figure 131. The relation of elevation to yield in 1912 is shown in 
table 2: 



TABLE 2. Relation of Elevation to Yield on 327 Long Island Farms in 1912 



Elevation 

(feet) 


Number 
of farms 


Average 

yield 
per acre 
(bushels) 


Average 
amount 
of seed 

used 
per acre 
(bushels) 


Average 
value of 
manure 

and 
fertilizer 
per acre 


Average 

elevation 

(feet) 


1- 50 


157 
87 
53 
22 

8 


178.3 
157.5 
184.3 
188.8 
196.3 


12.9 
12.0 
12.4 
12.2 
13.4 


$35.31 
27.71 
32.20 
33.01 
31.65 


26.4 


50 - 100 


64.8 


100-150 


117.2 


150 - 200 


167.7 


200 and over 


218.1 






Total 


327 


















175.3 


12.5 


$32.39" 


65.5 









1160 



Earle V. Hardenburg 



Altho there is no proof in table 2 that the yield increases with an increase 
in elevation, there is a slight indication that this may be true. The farms 
located at 50 to 100 feet elevation had a lower yield than those at the 
lowest elevation, partly because they received less seed and fertilizer 
than any other group. Furthermore, the farms at the lowest elevation 
received slightly more than the average amount of seed and fertilizer per 
acre. It is improbable, however, that the wide difference in yield between 
the two groups at the lowest elevations was due entirely to .differences 
in amount of seed and fertilizer. There may have been some basic reason 
why the 87 growers at the 50-to-lOO-feet elevation used the least seed 
and the least fertilizer, which would account in part for the lower yield. 
No such reason is apparent, however, from the data at hand. 

Influence of elevation in Steuhen County 

The average elevation of the farms visited in Steuben County is greater 
than in any other of the regions concerned in this survey, it being 1659.2 
feet. The elevation varies from 1200 to 2100 feet, a range of 900 feet, 
and within this range there is a considerable variation in the soil types, 
as is shown later in table 13 (page 1770). A sununary of the average 
yields obtained at various elevations is given in table 3: 



TABLE 3.. Relation of Elevation to Yield on 355 Steuben County Farms in 1912 



Elevation 
(feet) 


Number 
of farms 


Average 

yield 
per acre 
(bushels) 


Average 

unharvested 

yield 

per acre 

(bushels) 


Average 
elevation 

(feet) 


1200-1300 


9 
36 
39 
46 
46 
63 
61 
34 
21 


148.8 
156.6 
129.7 
136.4 
133.9 
131.6 
138.3 
134.6 
124.7 


24.6 
13.1 
20.5 
20.0 
24.1 
29.0 
30.7 
27.9 
17.0 


1,243.6 


1300- 1400 


1,336.0 


1400-1500 

1500-1600 

1600- 1700 


1,426.2 
1,530.4 
1 , 630 . 2 


1700-1800 


1,732.1 


1800-1900 


1,829.7 


1900 - 2000 


1,920.4 


2000 - 2100 


2,033 4 






Total 


355 
















Average. . . 




136.4 


, 24.2 


1,659 2 









A general tendency for yields to decrease as elevation increases is 
ndicated by table 3. This is counter to the expected influence of altitude, 
and may be explained by the fact that the soil at the higher altitudes of 



A Study of Factors Influencing the Yield of Potatoes 1161 

this region is heavier and of lower natural fertility. Further evidence 
of this condition is found in the figures showing a greater percentage of 
unhar vested yield due to blight rot, which is so common in these heavier 
soils, at the higher elevations. 

The Green Mountain, or white-sprout, type of potato withstands less 
heat than does the Rural, or blue-sprout, type. Where the growing- 
season temperature is relatively cool, as in Franklin and Clinton Counties 
and on Long Island, the white-sprout type is therefore more common. 
In Steuben County, of 94 farms growing the white-sprout potatoes, 61 
per cent were located above 1660 feet elevation and only 39 per cent were 
located below this level. Of 239 farms growing the blue-sprout type, 
50 per cent were above and 50 per cent were below 1660 feet elevation. 
There is some tendency, therefore, to grow more of the white-sprout type 
at the cooler altitudes. 

Influence of elevation in Monroe County 

The range of elevation in Monroe County is between 400 and slightly over 
800 feet. Little opportunity is therefore afforded to study the influence 
of this factor in this region. The figures in table 4, interpreted in the light 
of average seed and fertilizer used, show that elevation has some tendency 
to increase 3deld. 

TABLE 4. Relation of Elevation to Yield on 296 Monroe County Farms in 1913 



Elevation 

(feet) 


Number of 
farms 


Average 

yield 
per acre 
(bushels) 


Average 
amount of 
seed used 
per acre 
(bushels) 


Average 

value of 

manure and 

fertihzer 


400-500 

500-600 

600-700 

700-800 

800 and over 


.30 
107 
129 

23 

7 


130.5 

122.8 
116.0 
165.2 
225.4 


12.6 
12.5 
12.4 
12.5 
14.7 


114.03 
11.20 
10.86 
11.56 
11.39 


Total 


296 




















127.1 


12.5 


$11.34 









Influence of elevation in Franklin and Clinton Counties 

A variation of over 1500 feet elevation in the farms in Fra:nklin and 
Clinton Counties affords excellent opportunity for the study of the influence 
of elevation on yield. The summary given in table 5 shows a rather marked 



1162 



Earle V. Hardenburg 



•rABLE 5. Relation of Elevation to Yield on 290 Franklin and Clinton County 
Farms in 1913 



Elevation 
(feet) 


Number 
of farms 


Average 

yield 
per acre 
(bushels) 


Average 
amount 
of seed 

used 
per acre 
(bushels) 


Average 
value of 
manure 

and 
fertilizer 


Average 
elevation 

(feet) 


300 - 600 .... 


33 
19 
31 

47 

101 

42 

17 


154.8 
154.9 

185.1 
184.0 
179.1 
191.0 
193.4 


11.6 
10,9 
11.5 
12.1 
12.2 
12.5 
11.8 


$12.90 
11 12 
13.09 
13.10 
12.72 
13.22 
14.13 


437.7 


600 - 800 ... 


697.1 


800-1000 


895.5 


1000- 1200 


1,094.4 


1200-1400 


1,296.9 


1400- 1600 


1,468.6 


1600- 1850 


1,709.7 






Total 


290 


















177.3 


11.9 


$12.91 


1,038.2 









infliienco of this factor. With the amounts of seed and the vahie of manure 
and fertihzer used approximately equal, the best yields were produced at 
the higher mountain elevations. 

Since the increase in elevation for this region is accompanied by a con- 
siderable variation in soil type, a part of the increase in yield at the higher 
levels may be due to the latter factor. However, since Franklin County 
has not been soil-surveyed, it is impossible here to measure accurately 
the influence of the soil. Very little difference in soil type was evident 
between the Dover fine sandy loam of the lower elevations and the 
Caloma fine sandy loam of the higher elevations in Clinton County. 

CROP ROTATION 

The benefits of crop rotation to a heavy-feeding cultivated crop such as 
potatoes have long been recognized. The crop survey as a means of com- 
paring various rotations in a given region, however, has very limited possi- 
bilities, for in the older farming regions the same general type of rotation 
is followed thruout. Very few tests have thus far been made by the experi- 
ment stations to determine the most suitable place in the rotation and the 
best length of rotation for potatoes in a given region. Probably the most 
valuable work has been done by Hartwell and Damon (1916) in their 
twenty-years comparison of different rotations of corn, potatoes, rye, and 
grass, at the Rhode Island Station. The principal feature of this work 
lies in a comparison of four-, five-, and six-j^ears rotations of potatoes, 
rye and rowen, grass, corn, the grass being left down for from one to three 
years. No stable manure was used, but complete commercial fertilizers 



A Study of Factors Influencing the Yield of Potatoes 1163 

were added to the sod each year. In the matter of fertihzers, Hartwell 
and Damon's experiment is not comparable to farm practice in New York, 
where httle or no commercial fertilizer is ever used, stable manure being 
generally applied, instead, as a top dressing, during the last year of sod 
or perhaps just before plowing for corn or potatoes. The average yields 
per acre of potatoes obtained by Hartwell and Damon, in the rotations 
including grass for one, two, and three years, were 200, 199, and 223 
bushels, respectively. It appears that their commercial-fertilizer treat- 
ments were sufficient to maintain a maximum condition of sod thruout the 
three years. 

A test on the influence of various fertilizers on potatoes, conducted at 
the Rothamsted station, is reported by Hall (1905). In this test the crop 
was grown for twenty-six consecutive years on the same land, and under 
each treatment the yields declined during the later as compared to the 
earlier years of the test. Long Island is the only section in New York 
in which the crop is grown without rotation, and it is only the in- 
creased use of fertilizers that has maintained yields there. Not only is it 
difficult to get sufficient stable manure for the potato crop on Long Island, 
but many growers do not find it economical to haul fertilizer in this form so 
great a distance as would often be necessary. Consequently, each year 
more than a third of the growers sow a cover crop of rye after potatoes. 
Some use the cover crop every year, while others use it only every second 
or third year, and some not at all. In the consideration of the influence of 
cover crops on yield, only those fields are included on which a cover crop 
was grown in the fall and winter preceding the potato crop. In table 6 
the average yields that are obtained directly after cover crops, are com- 
pared with those obtained when no previous cover crop had been used. 

TABLE 6. Relation of Cover Crop to Yield on 313 Long Island Farms in 1912 



Treatment 



Number 
of farms 



Average 

yield 
per acre 
(bushels) 



Average 
amount of 
seed used 
per acre 
(bushels) 



Average value 

of manure and 

fertilizer per 

acre 



Cover crop 

No cover crop . 



Total. 



131 
182 



174.1 
177.3 



12.6 
12.5 



313 



$32.61 
32.25 



Average . 



175.5 



12.5 



$32.40 



The figures given in table 6 should not be construed to mean that cover 
crops are not beneficial to the potato crop on Long Island, because the 



1164 



Earle V. Hardenburg 



yields obtained in the group listed as not using a cover crop may have been 
produced on farms which used a cover crop two or three years previously 
or on farms whose soil was naturally higher in organic content. Granting 
this, the data on cover crops for Long Island are not sufficient to indicate 
either advantage or disadvantage accruing from its use. It is true that 
in 1912 growers who had not sown a cover crop the previous fall did not 
attempt to supplement the soil fertility by using more fertilizer. This 
in itself may indicate that, in the main, only those growers who actually 
needed the cover crop to maintain yields were the ones who used it. 

The rotations followed in Steuben County, consisting usually of potatoes, 
grain, and hay, vary principally in the number of successive years that 
the hay and the grain are left on the same ground. Commercial fertilizer 
is applied lightly at the time of planting potatoes, and, altho what stable 
manure is available is put on the sod to be plowed for potatoes, there 
is seldom enough to cover the entire potato acreage. The yields of hay are 
largely dependent on the residual fertilizer left from that applied directly to 
the grain crops. Thus in the longer rotations, in which sod is left down for 
three or more years, only a poor supply of root and stubble residue is left 
to supply humus to the potato crop. A comparison of the influence on 
the yield of various types of rotations in this region is shown in table 7: 

TABLE 7. Relation of Rotation to Yield on 240 Steuben County Farms in 1912 





Manure or fertihzer on 
part of acreage 


Manure or fertilizer on 
entire acreage 


No manure nor fertilizer 
used 


Rotation 


Num- 
ber of 
farms 


Average 

yield 

per 

acre 

(bushels) 


Average 
amount 
of seed 

used 

per 

acre 
(bushels) 


Num- 
ber of 
farms 


Average 
yield 
per ■ 
acre 

(bushels) 


Average 
cost of 
manure 
and 
ferti- 
lizer 


Num- 
ber of 
farms 


Average 

Average amount 

yield of seed 

per used 

acre per 

(bushels) acre 

(bushels) 


Potatoes, grain, hay. . 
Potatoes, grain, hay. 


13 
117 
62 
25 
11 


177.0 
134.9 
122.7 
150.1 
143.0 


10.9 
10.3 
10.0 
9.2 

8.8 


8 
58 
26 
12 

5 


189.1 
150.1 
135.0 
160.9 
160.2 


$10.51 1 
13.98 7 
11.95 1 3 


150.0 
106.2 
103.6 

60.0 


7.5 
9.6 


Potatoes, grain, hay. 


10.5 


Potatoes, grain, grain, 
hay, hay 

Potatoes, grain, grain, 
hay, hay, hay 


13.34 
20.34 


1 


8.8 



Ehminating the factors of seed and fertilizer as given in table 7, the yield 
consistently decreased with each successive year that the sod remained in 
rotation. This shows the tendency of the seeding to become thinner and of 
less value as a source of humus for the potato crop, the older it becomes. 
The figures for the last two rotations in the table — which differ from the 
first three in that they contain two years of grain instead of one, and from 



A Study of Factors Influencing the Yield of Potatoes 1165 

each other only in the number of years of successive hay crops — show 
a higher average yield of potatoes with them than with the first three. 
This may be due to the additional residual fertilizer left from that applied to 
the extra year of grain, or to the factor of naturally better soil as indicated 
by the tendency to produce more grain. 

The type of rotation commonest in each region is indicated by the figures 
in table 8 on the percentage of total crop acres occupied by each crop 
listed. No fixed rotation is indicated for Long Island, where potatoes are 
grown for a varying number of successive years on the same land. The 

TABLE 8. Relative Importance of Crops on Farms Surveyed 



Crop 



Per cent of crop acres 



Long 



Steuben 
County 



Monroe 
County 



Eranklin 

and 
Clinton 
Counties 



Average 



Hay 

Potatoes 

Oats 

Corn for grain . 

Wheat 

Orchard 

Rye 

Corn for silage . 

Cabbage 

Sweet corn .... 

Beans 

Buckwheat. . . . 
Cauliflower .... 

Barley 

Garden truck. . 
Brussels sprouts 
Corn for fodder , 

Alfalfa 

Peas 

Oats and barley 
Sugar bush 



34.25 
21.50 
14.75 
5.75 
5.50 
2.75 
2.50 
1.75 
1.75 
1.50 
1.25 
1.25 
1.25 
1.00 
1.00 
0.50 
0.50 
0.50 
0.25 
0.25 
0.25 



figures for Steuben County indicate a rotation of potatoes, oats, hay 
two years; those for Monroe County, a rotation of potatoes with corn or 
beans or cabbage, oats, wheat, hay one to two years; and those for Franklin 
and Clinton Counties, a rotation of potatoes with corn, oats, hay three 
years. 

A review of the experimental literature on the influence of crop rotation 
in potato production shows a striking preference for either grass, or a 



1166 Earle V. Hardenburg 

legume productive of considerable vegetative growth, as a crop to precede 
potatoes. This is evidence of the efficient use which the potato crop is 
able to make of this form of organic material. Such legumes as cowpeas, 
soybeans, and crimson clover commonly precede potatoes in the Southern 
and the South Atlantic S.tates, while timothy, in combination with red or 
alsike clover, is used generally thruout the principal potato States. Alfalfa 
is considered the ideal legume to precede potatoes in the alfalfa belt of the 
West. The root and stubble residue from these crops not only contributes 
to the food requirements of the potato, but also improves the aeration, 
the temperature, and the moisture-holding ability of the soil. 

Generally speaking, the rotations of the three regions aside from Long 
Island are long enough not to serve as factors limiting yield except as the 
type of rotation may affect fertilizing practices. Inasmuch as the avail- 
able stable manure is not usually applied for the benefit of the hay crops, 
and the residual organic fertility is not thereby maintained or improved, 
the sod residue commonly turned under before potato planting is usually 
less valuable after a three-years stand than after a stand of shorter 
duration. 

VALUE OF LAND 

The farmer's estimate of farm land values is very often not based on 
productive value, altho this factor, together with the distance from rail- 
road and city and the salabihty of the farm, usually enters into the appraise- 
ment. A correlation of estimated value with average yields will show, 
in a measure, the extent to which productive ability of potato land enters 
into its evaluation. App (1916), studying the factors that influence 
farm profits on potato farms in Monmouth County, New Jersey, found a 
consistent tendency for farm acre values to decrease as distance from the 
railroad increased. His similar conclusions with respect to crop acre 
values and labor income, however, do not seem warranted from the data 
given. 

The figures obtained on land values in the regions surveyed represent 
the estimated selling value of potato land only. A more important factor 
than the distance from the post office, which was ascertained and used 
in making this estimate, would have been that of the distance from the 
nearest city, village, or railroad. 

Apparently, on Long Island, land valued up to $550 an acre is yielding 
an increased crop with the increase in value (table 9). However, it is 
true also that the increase in land values is accompanied by the use of 
more seed and more fertilizer, and by more spraying for blight. These 
combined factors would easily account for the consistent increase in yield. 
The farms showing a land value of over $550 an acre are located prin- 
cipally in Nassau County, at a considerable distance from the post office, 
and are appraised at their real-estate value. In fact, much of the land 
has been sold at fabulous prices for real-estate purposes and is now rented 



A Study of Factors Influencing the Yield of Potatoes 1167 
TABLE 9. Relation of Value of Land to Yield on 330 Long Island Farms in 1912 



Value 


Num- 
ber 
of 

farms 


Average 

yield 
per acre 
(bushels) 


Average 

distance 

from 

post 

office 

(miles) 


Amount 

of 
seed used 
per acre 
(bushels) 


Value of 
manure 

and 
fertilizer 
per acre 


Per cent 

of 

farms 

using 

bordeaux 


Less than $250 


118 
L32 
27 
53 


147.0 
184.7 
196.7 
191.9 


2.7 
2.3 
2.8 
5.6 


12.1 
12.6 
13.0 
12.7 


$30.24 
33.50 
35.24 


24 


$250-$400 


45 


$400-$550 


52 




32.73 


11 






Total 


330 








1 






175.5 


3.0 


12.5 


, $32.40 i 32 











back to the original owner who is again growing potatoes on it. Some- 
what less seed and fertilizer are used on these farms, and less spraying is 
done on them. 

In Steuben County, potato land valued up to $80 an acre gives increased 
yields with the increase in value (table 10). Tho the amount of seed used 

TABLE 10. Relation of Value of Land to Yield on 360 Steuben County Farms 

IN 1912 



Value 


Num- 
ber 
of 
farms 


Average 

yield 
per acre 
(bushels) 


Average 

distance 

from 

post 

office 

(miles) 


Amount 

of 
seed used 
per acre 
(bushels) 


Value of 
manure 

and 
fertilizer 
per acre 


Per cent 

of 

farms 

using 

bordeaux 


$25-$40 

$40-$50 

$50-$60 ■... 

$60-$70 


46 
111 
76 
44 
42 
41 


110.2 
134.1 
139.4 
144.4 
148.2 
145.1 


5.3 
4.2 
3.6 
3.6 
2.9 
2.5 


9.6 
10.4 
10.1 
10.4 
10.3 

9.5 


$ 7.93 
9.01 
10.86 
11.80 
12.29 
10.31 


4 
6 
8 



$7O-$80 





$80 and over 


5 


Total 


360 












Average ... 




136.4 


3.8 


10.1 


$10.14 


5 









per acre is about the same thruout, there is a tendency to spend more in 
manure and fertilizer for the higher-priced land. The real reason for 



1168 



Earle V. Hardenburg 



this is doubtless the relative cheapness with which manure and fertilizer 
can be handled by the growers nearest the villages. The increased yield 
of the higher-priced land may be due in part to this increase in the value 
of manure and fertilizer used. Land values decrease as the distance from 
the post office increases, in Steuben County. Distance, in fact, may 
largely determine the valuation of potato land. 

In Monroe County, as in Steuben County, the yields increased with the 
increase in land values (table 11), the yield increase being accompanied by. 



TABLE 11. 



Relation of Value of Land to Yield on 297 Monroe County Farms in 
1913 



Value 


Num- 
ber 
of 
farms 


Average 

yield 
per acre 
(bushels) 


Average 

distance 

from 

post 

office 

(miles) 


Amount 

of 
seed used 
per acre 
(bushels) 


Value of 
manure 

and 
fertilizer 
per acre 


Per cent 

of 

farms 

using 

bordeaux 


$ 50-1100 

$100- $150 

$150- $200 

$200- $250 


27 
145 
69 
56 


103.4 
128.3 
130.6 
129.3 


4.3 
2.6 
2.3 
2.3 


11.1 
12.5 
12.7 
13.0 


$10.86 
10.09 
12.02 
14.10 


19 
23 
35 
18 


Total 


297 

















Average 




127.0 


2.6 


12.5 


$11.33 


24 









TABLE 12. 



Relation of Value of Land to Yield on 300 Franklin and Clinton 
County Farms in 1913 



Value 


Num- 
ber 
of 
farms 


Average 

yield 
per acre 
(bushels) 


Average 

distance 

from 

post 

office 

(miles) 


Amount 

of 
seed used 
per acre 
(bushels) 


Value of 
manure 

and 
fertilizer 
per acre 


Per cent 

of 

farms 

using 

bordeaux 


$ 10-$ 25 


29 

105 

114 

42 

10 


160.2 
173.4 
189.0 
178.2 
176.9 


4.2 
3.5 
3.7 
2.5 
1.6 


10.2 
11.3 
12.9 
12 3 
13.0 


$12.35 
13.73 
12.79 
11.83 
15.02 





$ 25-$ 50 





$ 50-$ 75 


2 


$ 75 -$100 







10 






Total 


300 
















Average 




179,3 


3.4 


12.0 


$13.01 


1 









A Study of Factors Influencing the Yield of Potatoes 1169 

and doubtless largely due to, an increase in the amount of seed and in 
the value of manure and fertilizer used. Here also the land values tend 
to decrease as the distance from the post office increases. 

In Franklin and Clinton Counties there is a tendency to spend more 
for seed, fertilizer, and spraying, on the farms having the higher- valued 
potato land (table 12). This expenditure is apparently justified on 
land valued up to $75 an acre. Above that point, the average yield did 
not increase even with increased expenditure. This may be taken as an 
indication that such land was valued at more than its productive ability 
would justify. These more valuable farms are situated near Peru, in 
Clinton County, and are thus highly valued because of their location in 
the apple section of northern New York rather than on the basis of their 
adaptability to potato culture. 



It has not been possible to study the influence of soil on yield on Long 
Island and in Franklin and Clinton Counties. Altho Clinton County 
has been soil-surveyed, it is included in the tabulations with Franklin 
County, and the records taken were insufficient to justify the making of 
such a study on Clinton County alone. The Monroe County soils map, 
published by the United States Bureau of Soils, has been used in correlat- 
ing yield and other factors with the soils of that region. 

Professor E. 0. Fippin, formerly of the Department of Soil Technology 
at Cornell University, accompanied by the writer, made a reconnaissance 
soil survey of the surveyed area in Steuben County in the summer of 1916. 
Professor Pippin's familiarity with soil mapping in New York enabled 
him therefor to sketch the boundaries of the various soil types and series 
on the topographic sheets previously used in locating the surveyed potato 
fields. 

Nearly half of the crop in Steuben County is grown on the Lordstown 
soil series at an average elevation of 1718.2 feet. As indicated in table 
13, the highest average yield was obtained on this soil series in spite of the 
fact that only an average amount of seed was used and somewhat less 
than the average value of manure and fertilizer. In contrast to this, 
the Volusia soil series, located on the hilltops at an average elevation of 
1785.5 feet, yielded the lowest average yield of any series in spite of the 
fact that about the average amount of seed was used and more than the 
average value of manure and fertilizer. The principal difference between 
these two soil series lies in the somewhat darker color and the better 
ox'dized condition of the Lordstown series. It is true that the soils of 
this region become lighter in texture and of higher gravel and stone content 
as the valleys are approached. This condition is probably blamable, 
at least in part, for the higher percentage of blight rot on the heavier soils 



1170 



Earle V. Hardenburg 



at the higher elevations, as indicated in table 13. Altho very little spray- 
ing for blight was done in 1912, it was noted that the fields which were 
sprayed returned a higher average yield than those which were not sprayed, 
irrespective of the soil type. Apparently, depth of planting and date of 
planting are not influenced by soil type. 



TABLE 13. Relation of Soil Type to Yield on 293 Steuben County Farms in 1912 









Average 


Average 


Average 














Average 


unhar- 


value 


amount 


Per 










Num- 


yield 


vested 


of 


of seed 


cent of 


depth 


f^^ 


Average 


Soil type 


ber of 


per 


yield 


manure 


used 


farms 


of 




elevation 




farms 


acre 


per 


and 


per 


usmg 






(feet) 






(bushels) 


acre 

(bushels) 


ferti- 
lizer 


acre 
(bushels) 


bordeaux 


(inches) 


ing 




Volusia silt loam 




















and loam 


36 


115.9 


32.7 


$10.79 


10.2 





3.4 iMay 17 


1.785.5 


Lordstown silt loam 


151 


144.8 


25.2 


9.35 


10.9 


6 


3.1 'May 19 


1,718.2 


Wooster gravelly 




















19 


126 9 










3.2 iMay 17 




Rodman gravelly 
















loam 


59 


142.1 


24.0 


11.76 


10.1 


2 


3.0 Mav 22 


1,496.5 


Chenango gravelly 




















loam 


28 


140.4 


23.7 


9.25 


11.0 


7 


3.1 


May IS 


1,364.6 


Total 


293 


















Average 




139.6 


25.1 


$10.08 


10.6 


* 


3.1 


May 19 


1,642.8 



In the area surveyed in Monroe County, four soil series are concerned — 
Ontario, Dunkirk, Clyde, and Genesee. In all, fourteen soil types are 
involved, but because of the small number of farms on some of these types, 
only those shown in table 14 are used in correlating soil with yield and 
other factors. On the basis of seed used, of value of manure and ferti- 
lizer, and of percentage of farms using bordeaux, the Dunkirk fine sandy 
loam and the Dunkirk fine sand are naturally the best for potatoes from 
the standpoint of yield, among the types considered. Altho in 1913 
nearly half of the crop in the surveyed area was grown on Ontario fine 
sandy loam, under at least average cultural treatment, it gave the lowest 
average yield per acre of any series studied. As indicated in the summary 
of table 14, the soil types of the Dunkirk series seem to give higher yields 
than those of the Ontario series. The average amount of seed, fertilizer, 
and spraying was about the same in both series. Here, as in Steuben 
County, depth and date of planting do not seem to be infiuenced by any 
difference in soil type. The average elevation of the two soil series sum- 
marized is almost identical. In brief, with more seed, more fertilizer, 
and a higher percentage of area sprayed with bordeaux, the Ontario soils 
yielded 20 bushels per acre less than did the Dunkirk soils. 



A Study of Factors Influencing the Yield of Potatoes 1171 

TABLE 14. Relation of Soil Type to Yield on 253 Monroe County Farms in 1913 



Soil type 


Num- 
ber of 
farms 


Average 
yield 
per 
acre 

(bushels) 


Average 

value 

of 

manure 
and 

fertii- 
lizer 


Average 

amount 

of seed 

used 

per 

acre 

(bushels) 


Per 

cent of 

farms 

using 

bordeaux 


Average 

depth 

of 

planting 

(inches) 


Average 

date 

of 

planting 


Average 

elevation 

(feet) 


Dunkirk fine sandy 

loam 

Ontario fine sandy 


20 

124 

32 
52 

11 
14 


186.6 

122.0 

123.1 
124.2 

123.7 
137.2 


$11.45 

11.09 

9.83 
12.99 

9.01 
11.24 


12.4 

12.6 

12.0 
13.0 

11.0 
12.4 


15 

19 

25 
6 

27 
21 


2.9 

2.9 

3.1 
3.3 

3.3 
3.7 


June 14 

June 3 

June 7 
June 6 

June 8 
June 7 


659.3 
595.2 


Dunkirk gravelly 


586 2 


Ontario loam 

Dunkirk gravelly 

sandy loam 

Dunkirk fine sand. . . 


582.0 

573.6 
515.0 


Total 


253 





















Average 




128.3 


$11.31 


12.5 


17 


3.1 


June 6 


591.0 


Summary 

Ontario series 

Dunkirk series 


176 

77 


122.7 
142.6 


$11.65 
$10.42 


12.7 
12.0 


27 
17 


3.0 
3.2 


June 5 
June 10 


591.3 
590.5 



The study of plowing as to its bearing on yield is treated under two head- 
ings — time of plowing and depth of plowing. The average date of plow- 
ing was obtained by averaging the actual dates of plowing for each region. 
It is recognized, of course, that this date will vary from year to year, 
depending on seasonal conditions. The only region in the State in which 
fall plowing was done to any appreciable extent was Franklin and Clinton 
Counties. To determine the depth of plowing, the grower was in each 
case asked to give his estimate of the actual depth, in inches, which he 
plowed for potatoes. 

Time of plowing 

For many years, such advantages as increased liberation of plant food, 
elimination of injurious insects, and improved soil texture, have been 
pointed out in favor of fall plowing. Very little experimental evidence 
has been presented, however. Dickens (1914) has furnished data covering 
two years of work at five substations in Kansas, all showing a decided 
increase in yield on fall-plowed as compared to spring-plowed land for 
potatoes. A summary of the data on the season at which potato land 
was plowed in each of the surveyed regions in this study is given in 
table 15: 



1172 Earle V. Hardenburg 

TABLE 15. Per Cent of Potato Land Fall- or Spring-plowed in the Areas Surveyed 



Time of plowing 



Long 


Steuben 


Monroe 


Island, 


County, 


County, 


1912 


1912 


1913 


1.5 


1.7 


0.33 


2.1 


8.0 


0.00 


96.4 


90.3 


99.67 



Franklin 

and 

Clinton 

Counties, 

1913 



Fall 

Part fall and part spring 
Spring 



57.0 
16.0 
27.0 



The average dates of spring plowing in 1912 for Long Island and for 
Steuben County were April 3 and April 29, respectively. The average 
dates of spring plowing in 1913 for Monroe County and for Franklin and 
Chnton Counties were May 15 and May 12, respectively. No speculation 
as to the reason for the greater proportion of fall plowing in Franklin and 
Clinton Counties is offered, but it is presumed to be due as much to weather 
conditions for the year as to labor competition with work on other crops. 
The comparative yields on land plowed at the different seasons in Franklin 
and Clinton Counties are shown in table 16: 



TABLE 16. 



Relation of Time of Plowing to Yield on 300 Franklin and Clinton 
County Farms in 1913 



Time of plowing 


Num- 
ber 
of 

farms 


Average 

yield 
per acre 
(bushels) 


Average 
amount 
of seed 
used 
per acre 
(bushels) 


Average 
value of 
manure 

and 
fertilizer 


Average 
acreage 

of 
potatoes 


Fall 

Part fall and part spring 

Spring 


171 

48 
81 


183.7 

173.9- 

173.2 


12.4 
11.6 
11.5 


$12.81 
14.47 
12.46 


7.2 

7.2 
7.2 


Total 


300 














Average 




179.3 


12.0 


$13.01 


7.2 



In view of the fact that about a bushel more of seed and a slightly higher 
value of manure and fertilizer were used on the fall-plowed land, the dif- 
ference in yield of 10.5 bushels per acre in favor of fall plowing may not be 
entirely due to a difference in the time of plowing. There is no indication 
that fall plowing is commoner on the larger potato acreages, since the 
average acreage was the same in all three groups. 



A Study of Factors Influencing the Yield of Potatoes 1173 

Depth of vlounng 

It might be expected that a crop such as the potato, which develops 
underground and is subject to varying conditions of soil moisture and 
soil texture, would be influenced by the factor of depth of plowing. How- 
ever, no actual experiments with this problem have come to the writer's 
attention. Dickens (1914) states that shallow plowing has given the best 
results on loamy soil at the Kansas station. Stone (1905) states that 
at the Cornell station, deep plowing on the Dunkirk gravelly soil gave the 
best results. Generall}'^ speaking, shallow plowing has been recommended 
for heavy soils and deep plowing for light soils. 

The possibility of drawing definite conclusions from a study of a factor 
depending so much on the grower's estimate and on only one year's results, 
is necessarily limited. This is one of the factors that for its ultimate solu- 
tion must depend upon carefully controlled experiments on a given soil 
type in each region concerned. From the following discussion of the regions 
herein considered, it would appear that depth of plowing is an important 
factor only on soils of either extreme of texture — deep planting increasing 
the area for tuber development in heavy soils, and providing for planting 
at the moisture-table depth in light soils. 

Depth of plowing on Long Island 

Altho the soils of Long Island are noticeably lighter than those of any 
other potato region in the State, a marked correlation of depth of plowing 
with yield is evident in table 17. An increase in the depth of plowing was 
accompanied by the use of more seed and fertilizer per acre and a greater 

TABLE 17. Relation of Depth of Plowing to Yield on 328 Long Island Farms in 1912 



Depth of plowing 

(inches) 


Num- 
ber 
of 
farms 


Average 

yield 
per acre 
(bushels) 


Average 
amount 

of 
seed used 
per acre 
(bushels) 


Average 
value of 
manure 

and 
fertihzer 


Average 
number 
of times 
sprayed 

with 
bordeaux 


Less than 5 . . 


26 
60 
119 
65 
36 
22 


163.7 
162.9 
173.8 
174.1 
188.6 
202.1 


11.4 
11.6 
12.8 
12.9 
12.7 
12.9 


$30.01 
30.53 
32.15 
33.65 
35.26 
32.13 


2.5 


5-6 


3.0 


6-7 


3,0 


7-8 


3.3 


8-9 


3.4 




3.6 






Total 


328 


















175.6 


12.5 


$32.42 


3.1 









1174 



Earle V. Hardenburg 



frequency of spraying. These factors contributed in some degree to the 
greater yield apparently resulting from the deeper plowing. In answer 
to the question whether the deeper plowing was accompanied by deeper 
planting, it may be stated here that, whereas the Long Island fields were 
plowed at about the same average depth as those of the similarly light 
soils of Franklin and Clinton Counties, the average depth of planting was 
deepest on Long Island, and shallowest in Franklin and Clinton Counties, 
ot the four regions. Apparently, deeper plowing on Long Island is to be 
advised. 

By virtue of its descriptive value as well as its value as a means for 
measuring correlation, the biometrical method has been applied to this 
factor of depth of plowing for Long Island, as also for the other regions, 
and the result is shown in figure 132. The correlation coefficient, r, here 













Yield per 


acre, 


in bushels 
















§ 


K 


8 


g 


1 


lO 


o 


^1 


s 




g 


S 






















(M 


(M 


(M 




CO 








ci 


J_ 


i 


1 


3 


1 


t^ 


1 




1 


1 


J^ 








(M 


lO 




o 


§ 


s 




O 


Ol 


^ 


t^ 


o 






3 














""* 


CI 


(M 


<M 


(M 


CO 




_g 






1 


1 


2 




1 












5 


tS 


4 






4 


1 


9 


5 






2 








21 


ci 


5 




2 


5 


15 


12 


6 


10 


5 


2 




1 


2 


60 


1- 


6 


1 


2 


5 


11 


33 


16 


19 


11 


8 


8 


5 




119 


'^1 


7 




2 


5 


4 


16 


11 


12 


5 


7 


3 






65 


«« e! 


8 






5 


5 


7 


3 


8 


4 


1 


1 


1 


1 


36 


o—* 


9 






1 




1 


1 


8 


1 


2 




1 




15 


rSH 


10 






1 








2 


1 


1 


1 






6 


O. 


11 





























Q 


12 










1 
















1 



27 



37 



27 23 



13 



3 328 



81 42 60 

r = 0.159 =t 0.036 

Fig. 132. correlation of depth of plowing and yield on 328 long island farms in 1912 



has the value 0.159 ± 0.036. Inasmuch as the coefficient is positive and 
is more than three times its probable error, it shows a significant degree of 
correlation between depth of plowing and yield. Present-day biometri- 
cians are now well agreed that the significance of a coefficient is measured 
not alone by its absolute value, but in the light of its consistency with 
coefficients of other series or other years and its probable error. 



Depth of plowing in Steuben County 

In contrast to soil conditions on Long Island, the soils of Steuben County 
are the heaviest of any of the four regions. Nevertheless, a rather marked 
positive correlation between depth of plowing and yield is shown in table 
18. In this region, as on Long Island, the growers who plowed deeper 



A Study of Factors Influencing the Yield of Potatoes 1175 



TABLE 18. Relation of Depth of Plowing to Yield on 360 Steuben County Farms in 

1912 



. Depth of plowing 

(inches) 


Number 

of 

farms 


Average 
yield 

per 

acre 
(bushels) 


Average 

amount of 
seed used 
per acre 
(bushels) 


Average 
value of 
manure 

and 
fertilizer 


4- 6 


52 

258 

50 


125.8 
136.2 
149,4 


9.9 
10.1 
10.4 


$ 8 59 


6- 8 


10 39 


8-10 


10 54 






Total 


360 
















136.4 


10.1 


$10 06 









for potatoes were inclined to plant more seed and to use a greater value of 
manure and fertilizer. The difference in yield of nearly 24 bushels per 
acre resulting from a difference of 4 inches in depth of plowing is evidently 
due, in part at least, to the increase in depth of plowing. The coefficient 
of correlation shown in figure 133 is 0.190 ± 0.034, a value expressing 

Yield per acre, in bushels 






Fig. 





X 


rk 


J^ 


rk 


^ 


CO 


1 


.k 


J^ 


o 


J^ 


rk 


^ 


CD 


J_^ 








Oi 


lO 




o 




»o 




o 


(M 


i? 




o 




^ 
















"— ' 




'—' 




(N 












4 








2 


1 


2 


2 


















7 


5 




1 


4 


7 


11 


14 


5 


2 
















44 


6 




2 


13 


31 


32 


23 


13 


12 


4 


3 












133 


7 


1 


2 




18 


19 


26 


26 


18 


4 


4 




1 








126 


8 


1 




2 


5 


10 


12 


6 


6 


1 


3 










1 


47 


9 








1 




1 












1 








3 



2 5 26 64 73 78 52 38 9 10 2 1 360 
r = 0.190 ± 0.034 

133. correlation of depth of plowing and yield on 360 steuben county farms in 

1912 



significant correlation. Most of the crop in this region is grown on soils 
underlain at rather shallow depths with more or less impervious strata. 
Deeper plowing under these conditions would tend to enlarge the area 
adapted to maximum tuber development. 

Depth of plowing in Monroe County 

The soils of Monroe County may be considered intermediate in texture 
between those of Long Island and those of Steuben County. As a rule, they 
are deeper than those of the latter region. A study of table 19 shows no . 



1176 



Earle V. Hardenburg 



TABLE 1'9. Relation of Depth of Plowing to Yield on 261 Monroe County Farms 

IN 1913 



Depth of plowing 
(inches) 


Num- 
ber of 

farms 


Average 

yield 
per acre 
(bushels) 


Average 
amount of 
seed used 
per acre 
(bushels) 


Average 
value of 
manure 

and 
fertilizer 


4-7 


47 
93 
90 
31 


136.4 
134.2 
132.5 
145.0 


11.7 
12.2 
12.7 
14.5 


$11 95 


7-8 


10 97 


8-9. ... 


12 05 


9 and over. . 


11 42 






Total . . . 


261 
















135.6 


12.6 


$11.57 







apparent relation between depth of' plowing and yield. With approxi- 
mately the same fertilization for each depth of plowing, the slight tend- 
ency for increased yields at the deeper plowing may easily be attributed to 
the larger amount of seed planted. 

The coefficient of correlation shown in figure 134 is 0.006 ± 0.039. Both 



^ ci 



Yield per acre, in bushels 

lO O lO Q "5 

<>) lO t^ O (M 

1— I rt 1— I <M (N 

^ ci ^ ci ^ 

O O) lO t^ O 



J. ci 









1 


1 










1 








I 




2 


7 


12 


8 


12 


5 


4 


2 










52 




2 


10 


19 


24 


18 


13 


10 


9 


1 






1 


100 


1 


1 


16 


30 


11 


20 


13 


10 


3 




1 






106 




2 


4 

1 


8 


6 


9 
1 


1 
2 




1 


2 




1 




33 

5 



1 299 



Fig. 134. 



7 38 70 50 60 34 24 8 4 1 
r -= 0.006 ± 0.039 

correlation of depth of plowing AND YIELD ON 299 MONROE COUNTY FARMS 
IN 1913 



the coefficient and its probable error indicate alack of relationship between 
depth of plowing and yield for this region. Apparently the minimum 
depth of plowing was sufficient for maximum production in Monroe 
County soils. 

Depth of plowing in Franklin and Clinton Counties 

The figures shown in table 20 indicate that depth of plowing does not 
influence yields in Franklin and Clinton Counties. Tho the amount of seed 



A Study of Factors Influencing the Yield of Potatoes 1177 



TABLE 20. Relation op Depth of Plowing to Yield on 299 Farms in Franklin 
AND Clinton Counties in 1913 


Depth of plowing 
(inches) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Average 
amount of 
seed used 
per acre 
(bushels) 


Average 
value of 
manure 

and 
fertilizer 


4-5 


23 
70 
118 
52 
36 


175.5 
180.3 
179.2 
180.4 
179.6 


11.3 
11.4 
12.3 
11.9 
12.7 


$14.51 


5-6 


12.37 


6-7 


13.33 


7-8 


13.38 


8-10 


12.07 






Total 


299 
















179.3 


12.0 


$13.01 









planted was increased slightly as the depth of the plowing was increased, 
the amount of fertilizer used was not increased. Consequently there would 
be ample opportunity for any influence of depth of plowing to be reflected 
in the yields under this method of study. The coeflacient shown in figure 
135 is 0.028 ± 0.039, and indicates no relationship between the depth of 
plowing and the yield. 



Yield per acre, in bushels 



s 



^ (M 



S 4 

■S 5 

•S 6 

rt 7 

'^^ 
.3 9 



.k 


1 

o 


^ 


s 




1 


i 


1 


^ 




1 


1 


3 


6 


8 


1 


2 


1 




23 


5 


3 


11 


16 


19 


6 


3 


5 


2 


70 


2 


13 


23 


17 


32 


16 


8 


5 


2 


118 


2 


5 


8 


8 


10 


10 


8 


1 




52 


1 


4 


4 


5 


6 


5 


4 


2 


1 


32 


1 




1 




1 




1 






4 



12 



26 50 



26 



14 



299 



Fig. 135. 



76 38 
r = 0.028 ± 0.039 

correlation of depth of plowing and yield on 299 FRANKLIN AND 
CLINTON COUNTY FARMS IN 1913 

MANURE AND FERTILIZER 

The commercial-fertilizer industry, as a country-wide enterprise, began 
in the Eastern States and dates from about 1860. Previous to that time, 
the potato crop depended for its plant food largely upon the natural 
available supply of the soil, supplemented by applications of barnyard 
manure. Manure has been recommended by many experiment stations 
as perhaps the best source of nitrogenous plant food for this crop. How- 
ever, as the acreage increased in the East and the soils became more 



1178 Earle V. Hardenburg 

impoverished, the need for a commercial source of plant food became 
imperative. Today there are few crops which require more and respond 
better to fertilizer than do potatoes, tho even yet commercial fertilizer 
is used very little on the newer potato lands of Michigan, Wisconsin, and 
Minnesota. From the beginning of the fertilizer industry, hundreds of 
tests have been conducted by the eastern state experiment stations to 
determine the influence on the yield of potatoes of such factors as the 
amount of fertilizer used, its analysis, and the time and method of its 
application. According to Whitney (1910), 1769 such tests were conducted 
between 1868 and 1908, a period of forty years. Of all the tests made 
up to 1908, nearly 72 per cent fall within the ten-years period from 1890 to 
1900. Twenty-three States contributed to these tests, and about 57 per 
cent of the total were made in New York, Ohio, and New Jersey. Whitney 
states that it is impossible to draw conclusions even from an average of simi- 
lar experiments among those listed, since the variation in the yields of check 
plots of individual experiments sometimes ranges as high as 900 per cent. 
The crop survey has been found to have its limitations in the study of 
such questions as best analysis, best amount, or best source of ingredients, 
of a fertilizer to be used for potatoes. It is generally impossible to get 
information from the grower as to the analysis or the source of the elements 
of the fertilizer he has used. Many growers who were questioned had 
been more impressed by the brand name or by the price paid for the 
fertilizer than by its analysis. An attempt to correlate the amount of 
fertilizer per acre with the yield resulting was found impracticable with- 
out knowledge of its analysis, owing to the fact that large applications of 
a cheap fertilizer might be no more than equivalent to small applications 
of a high-grade fertilizer. Furthermore, many growers used manure 
in place of fertilizer, or vice versa, while many others used both on the 
same acreage. The study of the influence of manure and fertilizer on 
yield in the surveyed regions has therefore been made on the basis of the 
combined value per acre of manure and fertilizer. Estimates of the value 
of the manure used, made by the grower, and the prices he paid for fertilizer, 
have been used. In determining the proportion of the total value of the 
manure received by the potato crop, depending on the time and place of 
its application, 50 per cent of its value was charged if it was applied directly 
to the potato crop, 30 per cent if it was applied to the crop just preceding 
the potatoes, and 20 per cent if it had been applied two years before 
potatoes. This evaluation of residual manure is not based on exact 
experimental knowledge, but is presumed to represent the approximate 
availability of stable manure for successive crops. The Department 
of Agricultural Economics and Farm Management at Cornell University 
estimates that, on the heavier soils, 40, 30, 20, and 10 per cent of the 
value of manure is received by the first, the second, the third, and the 
fourth crop after its application, respectively. On lighter soils, which 



A Study of Factors Influencing the Yield of Potatoes 1179 



are more subject to leaching, probably a charge of 50 per cent to the first 
crop would be more nearly correct. A uniform basis of evaluation has 
been applied in this study. 

Home-mixed fertilizers 

Potato growers have never adopted the practice of mixing their own 
fertilizer, even in the regions where potatoes are raised on a very extensive 
scale. The advantage of using home-mixed fertilizers has usually been con- 
sidered to lie in a saving in cost rather than in an increase in yield. Woods 
and Bartlett (1909) compared several home-mixed fertilizers with a 
common ready-mixed commercial fertilizer of the same analysis. They 
found only a very slight advantage, on the average, in favor of the home- 
mixed fertilizers. 

In table 21 is shown the relative extent to which home mixing is practiced 
in the regions surveyed. These figures indicate that an average of about 



TABLE 21. Per Cent of Growers Using Home-mixed Fertilizer on Potatoes 


Long Island 


Steuben County 


Monroe County 


Franklin and 
Clinton 
Counties 


6 


5 


10 


1 



5,5 per cent of the potato growers in New York mix their own fertilizer 
for potatoes. A comparison of the various ingredients which constitute 
the home-mixed fertilizers used in these four regions is given in table 22 : 



TABLE 22. 



Per Cent of Growers Using Various Ingredients in Home-mixed 
Fertilizers 



Ingredient 



Long 


Steuben 


Monroe 


Island, 


County, 


County, 


1912 


1912 


1913 


95 


26 


3 


90 


84 


100 


95 


62 


87 


95 





10 


5 





13 


10 





10 


10 


5 








60 


10 


5 


21 


13 


10 


5 





55 









Franklin 

and 
Clinton 
Counties, 

1913 



Nitrate of soda 

Acid phosphate 

Muriate of potash 

Tankage 

Blood and tankage 

Dried blood 

Bone meal 

Nitrate of soda and dried blood 

Sulfate of potash 

Raw rock phosphate 

Fish scrap 



100 
75 

100 



25 







1180 Earle V. Hardenburg 

The percentages shown in table 22 indicate that on Long Island, nitrate 
of soda and tankage are used almost universally as the sources of nitrogen 
in home-mixed fertilizers. As is typical of coast regions, much fish scrap 
also is used for its nitrogen content. Acid phosphate is the principal 
source of phosphoric acid, altho ten per cent of the growers who mix their 
own fertilizers on Long Island use bone meal, and an equal number use 
raw rock phosphate, for the phosphoric acid supply. Of the potash supply 
95 per cent comes from muriate of potash, and the remaining 5 per cent 
comes in the sulfate form. 

In Steuben County, nitrate of soda and dried blood used together was 
the main source of nitrogen, no tankage being used by the five per cent of 
growers who mixed their own fertilizer. Phosphoric acid was obtained by 
eighty-four per cent of these growers from acid phosphate, and five per cent 
obtained it from bone meal. More sulfate of potash was used in this 
region than in any of the other regions surveyed, altho 62 per cent of all 
the potash was obtained in the muriate form. 

One-tenth of the growers visited in Monroe County mix their own 
fertilizer. About an equal number of these growers obtained their nitro- 
gen supply from dried blood and from tankage. A few used nitrate of 
soda. All of these growers obtained their phosphoric acid from acid 
phosphate. Muriate of potash was used by eighty-seven per cent of the 
growers, while thirteen per cent used the sulfate form for potash. 

Only one per cent of the growers in Franklin and Clinton Counties 
practiced home mixing. These men used only nitrate of soda for nitrogen 
and muriate of potash for potash. Acid phosphate was the principal 
source of phosphoric acid, altho a little bone meal was used. 

Summarizing for the four regions, it is seen that nitrate of soda is the 
commonest source of nitrogen. Generally, however, there is a tendency 
to mix nitrate of soda with either dried blood or tankage to furnish nitrogen 
in both a quickly and a slowly available form. Acid phosphate and 
muriate of potash are the principal sources of phosphoric acid and potash, 
respectively. 

Quantity and value of fertilizer 

The optimum amount of fertilizer for any crop necessarily depends 
on three principal factors: the available supply of plant food in the soil, 
the feeding requirements of the crop, and the net return per unit invested 
in fertilizer. Of these, the first two are usually measured by the yield 
per acre, regardless of cost, while the last is too often neglected. Macoun 
(1905) has shown, by a large number of analyses, that a 200-bushel yield 
of potatoes (exclusive of the tops) removes an average of 40 pounds of 
nitrogen, 20 pounds of phosphoric acid, and 70 pounds of potash, per acre 
of soil. This is about the same amount of nitrogen and phosphoric acid, 
but twice as much potash, as is removed by comparable yields of wheat 
and corn. 



A Study of Factors Influencing the Yield of Potatoes 1181 

Whitney (1910) summarized the many fertilizer experiments on potatoes 
in this country as to the influence of increasing the amount of fertilizer. 
So far as nitrate of soda, acid phosphate, and muriate of potash, used singly, 
are concerned, no consistent increase in yield has resulted from increasing 
the amount up to 500 pounds per acre. Increasing the amount of complete 
commercial fertilizer up to a ton and more per acre has, on the contrary, 
consistently increased the yields. The figures shown, however, would 
indicate that the increase in yield caused by amounts exceeding a ton has 
not been profitable. The same conclusions can be drawn regarding the 
use of manure in these experiments up to an amount not exceeding 20 
tons per acre. 

One of the oldest and best series of fertilizer experiments on potatoes, 
covering many years, was begun on Long Island in 1895, by the New York 
Agricultural Experiment Station at Geneva (Van Slyke, 1895). Com- 
parison of the yields from the use of 500, 1000, 1500, and 2000 pounds of 
fertilizer, up to- 1898, showed that it was not profitable to use more than 
1000 pounds per acre. The tests in 1898 showed 1500 pounds to be the 
most profitable amount. The curve of relation between the cost of fer- 
tilizer and the yield of potatoes, altho irregular, shows a positive correla- 
tion. Jordan (1900), reporting on a continuation of these Long Island 
tests in 1900, showed that whereas the highest yields were obtained with 
2000 pounds of fertilizer per acre, the greatest net gain from the crop 
resulted when only 1000 pounds was used. Rane and Hall (1904), at the 
New Hampshire station, found that 1500 pounds of commercial fertilizer 
was the most profitable amount to use, whether or not normal applica- 
tions of manure were used. Greater amounts of fertilizer, either with or 
without manure, were not profitable. Kohler (1910), in a triplicate series 
of plots conducted at the Minnesota station in 1910, showed that under 
Minnesota conditions it would not pay to use more than 800 pounds 
of fertilizer per acre, and in most of his tests 650 pounds gave the highest 
gain. The gain in yield from the elements used singly was almost negli- 
gible, their efficiency showing only when in combination. Kohler recom- 
mended the use of commercial fertilizer only when the supply of stable 
manure became insufficient in quantity. The experiments of Zavitz 
(1916) at the Ontario station, covering cooperative and station tests for 
five and three years, respectively, show a gain in yield, in most cases, 
resulting from an increase in either the amount or the value of the ferti- 
lizer used. Manure and fertilizer in combination, and manure alone, 
gave the greatest yields per acre and formed the cheapest fertilizer in 
both sets of experiments, not counting the cost of freight and application. 
So far as profit is concerned, therefore, the results of the Ontario experi- 
ments nuist be discounted. General experience has shown that the 
high cost of handling stable manure for potatoes on a large scale is often 
prohibitive. 



1182 



Earle V. Hardenburg 



Manure and fertilizer used in the four regions 

There is considerable variation in the amount of manure and fertihzer 
used in the four regions surveyed. On Long Island, where the crop is 
grown successively on the same land, /it is necessary to use large amounts of 
fertilizer in order to maintain the yields. In table 23 are given data 
concerning the use of manure and fertilizer in the four areas surveyed. It is 
obvious from this table that the use of manure on potatoes is closely asso- 
ciated with, and largely dependent upon, the dairy industry. 



TABLE 23. Summary of Manure and Fertilizer Used in the Four Regions Surveyed 







Average 












Per cent 


value 


Per cent 


Average 


Per cent 


Average 




of 


per acre 


of 


amount 


of 


amoimt 




growers 


of manure 


growers 


of 


growers 


of 


Region 


using 


and 


using 


fertilizer 


using 


manure 




manure or 


fertilizer 


fertilizer 


per 


manure 


per 




fertilizer 


on farms 


on 


acre 


on 


acre 




or both 


usmg 
them 


potatoes 


(pounds) 


potatoes 


(tons) 


Long Island 


100 


$32,42 


100 


1,922 


21 


5.2 


Steuben County .... 


95 


11 00 


39 


270 


93 


12.2 


Monroe County .... 


100 


14.84 


65 


406 


98 


12.0 


Franklin and Clinton 














Counties . . 


99 


13.14 


76 


516 


79 


11.0 







The first column of percentages in table 23 includes not only the growers 
who applied manure or fertilizer directly to potatoes, but also those who 
applied manure or fertilizer to the crop preceding potatoes, the potatoes 
receiving a certain percentage of value from the residue. On this basis, 
the average value of manure and fertilizer used on Long Island was more 
than twice that for the Monroe and the Franklin and Clinton County 
areas, and nearly three times that for the Steuben County region. ' The 
second and third columns of percentages in the table represent the 
growers who applied fertilizer and those who applied manure, respectively, 
directly to the potato crop, (The reader is referred to page 1178. for the 
method used in. evaluating manure.) It may be noted that manure is 
used directly for the potato crop by almost every grower in Steuben and 
Monroe Counties, while on Long Island only one grower in five uses it 
in this way. Growers on Long Island do not find it so practicable because 
of the expense of handling it for large acreages, the danger of scab infection, 
and the insufficiency of the supply for their fertilizer needs. In Steuben and 
Monroe Counties, manure is almost invariably applied to the sod land 
previous to plowing for potatoes. It is so applied also, but to a lesser 



A Study of Factors Influencing the Yield of Potatoes 1183 

extent, in Franklin and Clinton Counties, altho here much manure is 
applied to new seeding and some is apphed to oats. 

It is evident from table 23 that the region in which only a small propor- 
tion of the growers use fertilizer on potatoes is also the region in which the 
least fertilizer is applied to an acre. The average application of manure 
per acre in each region shown in the table, is reckoned not on the basis of 
those acres alone which received manure, but on the basis of the total 
potato acreage of those farms where manure was applied. Thus, on Long 
Island, manure is applied to only a small proportion of the total potato 
acreage per farm, while in the other regions most of the acreage is covered. 
The amount per acre averages nearly 10 tons, tho the rate varies from 
10 to 20 tons. 

The extent to which fertilizer and manure are used in Monroe County 
and in Franklin and Clinton Counties is fairly similar. The least fertilizer 
is used in Steuben County. Whether more could be used profitably in any 
of these regions is discussed in the subsequent studies. 

Value of manure and fertilizer on Long Island 

Inasmuch as the amount of seed used has been found to be a very 
influential factor in determining yield, this factor is eliminated as far as 
possible in the studies of other factors. Therefore, in studying the influence 
of the value of manure and fertilizer on yield, the records were first sorted 
into groups, according to the value of manure and fertilizer, and were then 
resorted according to the amount of seed used, as shown in table 24: 



TABLE 24. 



Relation of Value of Manure and Fertilizer to Yield on 330 Long 
Island Farms in 1912 





Less than 12 

bushels of seed 

per acre 


From 12 to 14 

bushels of seed 

per acre 


14 bushels and 

more of seed 

per acre 


Average of totals 


Value of manure 
and fertilizer per 
acre 


Num- 
ber of 
farms 


Average 
yield 

per 

acre 
(bushels) 


Num- 
ber of 
farms 


Average 
yield 
per 

acre 
(bushels) 


Num- 
ber of 
farms 


Average 
yield 

per 

acre 
(bushels) 


Num- 
ber of 
farms 


Average 
yield 

per 

acre 
(bushels) 


Less than $30 

$30-$40 

$40 and over 


67 
58 
14 


155.5 
172.1 

182.7 


43 
60 
23 


157.1 
174.0 
187.5 


13 
38 

14 


176.4 
196.2 
222.1 


123 
156 
51 


158.9 
180.1 
198.0 


Total 139 




126 




65 




330- 




Average 


166.0 




170.2 




197.8 




175.5 



1184 



Earle V. Hardenburg 



With the amount of seed used remaining constant, the yield was increased 
in every instance by an increase in the value of manure and fertilizer used. 
Furthermore, the yields were apparently sufficiently increased by the use 
of fertilizer to the value of at least $40 an acre, to make such applications 
profitable. It is evident that the maximum limit of fertilization in 1912 
did not exceed the point of optimum profit. 

The correlation between value of manure and fertilizer, and yield per 
acre, for this region is significantly expressed by the positive coefficient 
0.244 ±0.035 shown in figure 136. 

Yield per acre, in bushels 



ci J. ci 



S J^ 





(M lO 


t- 


o 


o5 


2 


t^ 


a 


CM 






^ 




$11-$15 






1 


















1 


$16-$20 




1 


3 


2 
















6 


$21-$25 




9 


12 


21 


9 


13 


2 


3 


1 






70 


$26-$.30 


3 


6 


9 


IG 


10 


16 


6 


1 


2 




2 


71 


$31 -$35 


1 3 


7 


6 


23 


14 


14 


11 


14 


4 






97 


^ $36-$40 




3 


1 


12 


5 


10 


4 


4 


3 


2 




44 


t $41-$45 




1 


3 


3 


2 


5 


3 




2 


4 




23 


^ $46-$50 








3 


2 




1 


1 




1 




8 


^ $51-$55 






1 




1 


1 








1 


1 


5 


$56-$60 






1 












1 






2 


$61-$65 






1 






1 












2 


$66-$70 



























$71-$75 



























$76-$80 








1 
















1 



6 27 



38 81 43 60- 27 
r = 0.244 ± 0.035 



23 13 



330 



Fig. 136. correlation of value of manure and fertilizer, and yield, on 330 long 
island farms in, 1912 



Value of manure and fertilizer in Steuben County 

In Steuben County the value of manure and fertilizer has been studied 
in a similar way. As appears in table 25, however, little manure and fertili- 
zer is used here. Altho the average results indicate an increase in yield 
from the use of as much as .|50 worth of manure and fertilizer per acre, 
the increased yield from applications of more than $20 worth per acre was 
not sufficient to cover the extra cost of the fertilizer. Therefore, in spite 
of the relatively small amount of fertilizer applied in this region, there may 
be other factors that limit the profit possible from larger applications. 
The coefficient of correlation between this factor and yield, for this region, 
is 0.289 ± 0.033, as shown in figure 137. 



A Study of Factors Influencing the Yield of Potatoes 1185 

TABLE 25. Relation of Value of Manure and Fertilizer to Yield on 155 Farms 
IN Steuben County in 1912 



Value of manure 
and fertilizer per 
acre 


Frojn 6 to 10 

bushels of seed 
per acre 


From 10 to 14 

bushels of seed 

per acre 


From 14 to 18 

bushel 5 of seed 

per acre 


Average of 
totals 


Num- 
ber of 
farms 


Average 
yield 
per 
acre 

(bushels) 


Num- 
ber of 
farms 


Average 
yield 
per 
acre 

(bushels) 


Num- 
ber of 
farms 


Average 
yield 
per 
acre 

(bushels) 


Num- 
ber of 
farms 


Average 
yield 
per 
acre 

(bushels) 


$ 4-$12 


25 
21 
11 


127.8 
141.3 
134.9 


41 
27 
17 


148.0 
162.4 
162.8 


5 
3 
5 


182.8 
287.1 
217.0 


71 
51 
33 


144.4 


$12-$20 


160.0 


$20-$50 


166.4 






Total 


57 




85 




13 




155 








Average 




133.9 




155.2 




213.7 




153.7 



Yield per acre, in bushels 



$ 0-$ 1 








1 














$ 1-$ 5 


1 2 


8 


20 


25 15 


13 


5. 


1 








^ S 6-$ 10 


1 


11 


22 


23 29 


18 


12 


1 


2 






1 $11-$15 




3 


13 


8 14 


8 


11 


2 


4 


1 


1 


t $16-$20 




1 


1 


5 7 


8 


4 


2 








a $21-$25 




1 


4 


4 6 


1 


5 


1 


1 






S3 $26-$30 








2 1 


4 








1 




^ $31-$35 






1 


2 




1 










•^ $36-$40 














i 








$41-$45 






















$46-150 














1 


1 







1 

90 

119 

65 

30 

23 

8 

4 

1 



2 



1 3 24 61 70 72 52 38 9 10 2 1 343 

r = 0.289 ± 0.033 

Fig. 137. correlation of value of manure and fertilizer, and yield, on 343 steuben 
county farms in 1912 



Value of manure and fertilizer in Monroe County 

The influence of manure and fertilizer in Monroe County is marked, and, 
except in a few cases where too few records were available, the results are 
consistent under constant amounts of seed used. It is evident from table 
26 that not enough manure and fertilizer was used in this region so that the 



1186 



Earle V. Hardenburg 



r2 "^ 



_^ ft 



1—1 <o 



1—1 01 
O ^ 

T— I 03 

£■03 
„^ 

O CO 

[Si 



1 2 ^ ' 



S S3' 



>•?>' 



^2 t- £"5 






T) ;^ (U ID 



<l1 



<1 



^•^s 



c33 »H <r S 






> 



^od 



2g' 



A Study of Factors Influencing the Yield of Potatoes 1187 



point of diminishing returns was reached. The yields increased sufficiently, 
up to the highest value of manyre and fertihzer used, to warrant the cost. 
Evidently it would be safe to recommend the use of larger amounts on 
potatoes in this region. The positive coefficient of correlation shown in 
figure 138 is 0.258 ± 0.036, a value significant and consistent with the 
coefficients for the other regions. 

Yield per acre, in bushels 

IQ O lO O lO OiOOioOiCO»CO 

^ ^ ,-i,-iC<)(N(MIMCOCOCg 

CO ^H CO 1-1 CO ^H CD 



3 ® 



$ 1-$ 5 
„ $ 6-$10 
£ =« $11-$15 
$16-$20 
$21-$25 
$26-$30 

$36-$40 

$41-$4.5 



O 





r^l 


>o 


t~- 


o 


^ 


lO 




o 


o5 


lO 


i^ 


o 


c^ 


















<N 














1 


7 


17 


9 


7 


3 
















1 


3 


18 


28 


20 


25 


14 


7 


3 


1 






1 






2 


10 
3 


14 

9 


11 

8 


14 

11 


8 
6 


10 
6 


4 


2 








1 




1 




1 

1 


1 

1 


3 
1 


3 


1 


1 


1 




1 







1 1 



44 

121 

76 

43 

10 

5 





1 

300 



1 7 38 70 50 61 34 24 8 
r = 0.258 ± 0.036 
Fig. 138. correlation of value op manure and fertilizer, and yield, on 300 monroe 
county farms in 1913 

Value of manure and fertilizer in Franklin and Clinton Counties 

A constant increase in yield for each increase in value of manure and 
fertilizer used, is shown in table 27 for the Franklin and CHnton County 

TABLE 27. Relation of Value of Manure and Fertilizer to Yield on 290 Franklin 
AND Clinton County Farms in 1913 



Value of manure 

and fertilizer 

per acre 


Less than 12 
bushels of seed 
per acre 


From 12 to 14 

bushels of seed 

per acre 


14 bushels and 

more of seed 

per acre 


Average of 
totals 


Num- 
ber of 
farms 


per 

acre 

(bushels) 


Num- 
ber of 
farms 


Average 
yield 
per 
acre 

(bushels) 


Num- 
ber of 
farms 


Average 
yield 

per 

acre 
(bushels) 


Num- 
ber of 
farms 


Average 
yield 

per 

acre 
(bushels) 


Less than $10 40 

$10-$15 40 

$15 and over 43 


149.2 
164.2 
170.4 


35 
39 

27 


182.1 
187.3 
190.0 


19 
26 
21 


174.8 
199.9 
221.7 


94 
105 
91 


167.1 
181.4 

188.2 


Total 


123 




101 




66 




290 








Average 


161.6 




186.2 




198.0 




178.8 



1188 



Earle V. Hardenburg 



region. The increase in yield obtained by growers using $15 worth or more 
of manure and fertihzer, over that obtained by growers using less, was 
sufficient to warrant the extra cost. Only twelve growers in this region 
used more than $25 worth of manure and fertilizer per acre. In view of 
the decreasing rate of increase in yield between the last two groups, 
it is doubtful whether a larger expenditure than $25 an acre would have 
shown a profitable increase. The correlation coefficient for this factor and 
yield, as shown in figure 139, is 0.169 ± 0.038. This indicates a significant 
relation, but one not so strongly marked as that for the other three regions. 



Yield per acre, in bushels 

lO O »C O •- 

(M lO t^ O C 

^ .-H ^ Ol c 



s 



$ 1-$ 5 
$ 6-SlO 
$11-$15 

S16-$20 

$21-$25 
$26-$30 

$36-$40 

$41-$4.5 



t^ 


o 


(N 


i2 


t^ 


o 


oi 


i{? 


t- 














(M 


(M 


<M 


(M 




2 


7 


3 


4 


2 


1 




1 




20 


2 


9 


13 


21 


23 


13 


6 


3 




90 


5 


3 


21 


15 


38 


14 


8 


5 


2 


111 


1 


6 


8 


10 


6 


7 


9 


3 


2 


52 


1 


1 


2 


1 


3 


2 


1 


1 


1 


13 




1 


1 


1 


2 


1 


1 


1 




8 
1 
2 






1 




2 






















1 






1 



11 



27 



38 



26 



14 



Fig. 139. 



49 52 76 

r = 0.169 ± 0.038 

CORRELATION OF VALUE OF MANURE AND FERTILIZER, AND YIELD, ON 298 FRANKLIN 
AND CLINTON COUNTY FARMS IN 1913 



Analysis of fertilizer 

The average potato grower of New York is even yet none too familiar 
with the significance of fertilizer analyses. As previously stated, it was diffi- 
cult to get information as to the analyses of the brands used, many of the 
growers having been more impressed by the price paid or the brand name. 
Most of the fertilizer experiments for some years have justified the practice, 
as found in the surveyed regions, of using fertilizers in complete form for 
potatoes. 

Aside from the more fundamental physiological processes stimulated by 
each of the essential plant-food elements in plant growth, nitrogen func- 
tions principally in producing foliage, phosphorus in hastening maturity, 
and potash in increasing starch production. These elements in combina- 
tion naturally maintain a balance of value in successful potato production. 

Whitney (1910), in summarizing fertilizer tests on potatoes up to 1908, 
showed that: (1) there has been a consistent increase in the average yield 
of potatoes with the increase in the number of minerals used in mineral 
fertihzers; (2) there has been a similar increase in the average yield from 
an increase in the number of minerals used in combination with organic 



A Study of Factors Influencing the Yield of Potatoes 1189 

• 
fertilizers; (3) the use of organic fertilizers in combination with minerals 
resulted in higher average yields than resulted from mineral fertilizers 
alone; and (4) manure and commercial fertilizers produced higher average 
yields than any other type of fertihzer. Ballou (1910) and Gourley (1910) 
substantiate these general conclusions in reporting the results of a fifteen- 
years comparison of nitrate of soda, acid phosphate, and muriate of potash, 
used both alone and in combination on potatoes. These tests have shown 
that, altho the cheapest cost of increase per bushel was obtained from the 
use of acid phosphate alone, the greatest profit per acre resulted from the 
use of the complete fertilizer. The Rothamsted station, in England 
(Hall, 1905), experimenting for twenty-six years and using five varieties 
of potatoes on a series of ten plots, compared the yields from plots receiv- 
ing ammonium salts alone, nitrate of soda alone, superphosphate alone, 
and mixed mineral fertilizer. The average yields resulting from these 
treatments yaried in the order listed, ranging from the lowest yields with 
ammonium salts to the highest yields with mixed mineral fertilizer. Since 
these plots grew potatoes successively for twenty-six years, and since 
potatoes yielded less with nitrogenous fertilizers than with mineral 
salts alone, it was concluded that " the potato finds a difficulty in obtaining 
ash constituents rather than nitrogen from an impoverished soil." Balen- 
tine (1894) conducted greenhouse experiments to compare the foraging 
power of the potato plant for phosphoric acid, with that of other crop plants. 
He used identical amounts and forms of nitrate and potash fertilizer, 
but varied the phosphatic form. He compared the results from equivalent 
amounts of phosphoric acid in mostly insoluble forms with those from the 
soluble form and with the check in each crop series. The results showed 
that the potato plant is not able to make use of this element in the insoluble 
form nearly so well as do wheat, corn, peas, and turnips. 

Because of its importance in stimulating the vigor and yield in the 
crop and in satisfying the feeding requirements of the plant, potash had 
occupied the most important place in potato fertilizers up to the time 
when this survey was made. Rane and Hall (1904) compared the yields 
from plots containing 5, 10, and 15 per cent of potash, I'espectively, and 
those from plots containing no potash at all. They found^ that at the 
New Hampshire station, altho the yield was increased up to 15 per cent 
of potash, the most profitable results came from the 10 per cent of potash 
in a complete fertilizer. Several years later T. C. Johnson (1916) com- 
pared complete fertilizers differing only in that they contained 3, 5, and 
7 per cent, respectively, of potash. He obtained the best results from the 
5-per cent fertilizer, since that containing 7 per cent of potash seemed to 
retard maturity and decrease the yield. Conner (1906), at the Florida 
station, compared complete fertilizers containing 7, 8, 9, and lO per cent 
of potash, respectively. Tho this was but a one-year test, the check 
plots averaged nearly as high yields as did the plots receiving potash, 



1190 Earle V. Hardenburg 

which indicates that probably potash is not a hmiting factor in the soil 
at the Florida station. 

Under the recent war conditions, growers in the Eastern States were 
forced to do without potash or to use less. "Woods (1918), at the Maine 
station, has attempted to determine the possibihty of obtaining satis- 
factory yields without this element. His average results for the three 
years 1915, 1916, and 1917 show that, whereas fairly good yields have 
been obtained with no potash, the yield has been increased 26 bushels 
an acre by the addition of 3 per cent of potash. The additions of 5 and 8 
per cent of potash have given practically no increase above that from 3 
per cent. The high percentage of potash previously used in Maine was 
evidently not needed, or else the soil had become temporarily stocked 
with a surplus. Chemical analyses have shown that the sandier soils 
of the coastal plain are more deficient in potash than the heavier soils 
farther inland. This fact and the more intensive cultivation of potatoes 
probably account for the larger amounts of potash previously used in 
these regions. It might be supposed, therefore, that yields of potatoes 
cannot long be maintained without this constituent. The recent studies 
of Dr. Oswald Schreiner, of the United States Department of Agriculture, 
on potash hunger in the Aroostook potato region, in Maine and in the 
Norfolk potato truck areas, bear out this conclusion. The writer has 
recently observed marked examples of potash hunger in the potato fields 
of Long Island. Evidently the shortage of potash is beginning to be felt. 

Of the two principal forms of potash — muriate, or the chloride form, 
and sulfate — the muriate has always been the more commonly used on 
this crop. The reasons for this are the greater cost and the lesser supply 
of the sulfate form. It is occasionally stated, tho the point does not 
seem to be borne out by much experimental evidence, that the chlorine 
in muriate of potash is detrimental to quality in the potato. There has 
generally been little difference bet;ween the two forms as to the yield 
resulting. Rane and Hunt (1897), in a one-year test, used 87 varieties 
of potatoes and obtained a very slight advantage in favor of muriate of 
potash. Many years later, Brooks (1914) obtained an increase in yield of 
11 bushels per acre in favor of the sulfate form, with an additional improve- 
ment in quality. 

The experiments of Conner (1906) show results from the use of various 
amounts of ammonia and of phosphoric acid in complete fertilizer, which 
not only are inconsistent but also show average yields not essentially 
different from those from the check plots. T. C. Johnson (1916), com- 
paring the results from 2, 4, and 8 per cent, respectively, of phosphoric 
acid in complete fertilizer, found the best results from the 8-per-cent 
analysis. His results with varying amounts of nitrogen were incon- 
clusive. Woods (1918), in a test to compare nitrogenous fertilizers in 
combinations of nitrate of soda, ammonium sulfate, and organic forms, 



A Study of Factors Influencing the Yield of Potatoes 1191 



thru the years 1914 to 1917, inclusive, found practically no advantage 
for any one form over another. 

Altho many different analyses of fertilizers were used in 1912 and 1913 
in the surveyed regions, the majority of growers in each region were 
buying fertilizers of the same analysis. In table 28 are shown the analyses 
of the fertihzers in commonest use at that time, in the four regions: 



TABLE 28. Commonest Analyses of Fertilizers Used in the Four R 
Surveyed 


EGIONS 


Rank 


Long 

Island, 

1912 


Steuben 

Coimty, 

1912 


Monroe 

County, 

1913 


Franklin 

and 

Clinton 

Counties, 

1913 


Used by majority 


3-8-7 
4-8-7 
5-8-5 


2-8-10 
0-10-8 
0-8-10 


2-8-10 
0-10-8 
0-8-10 


2-8-10 


Second in amount used 


0-10-8 


Third in amount used 


0-8-10 







Because of the higher percentage of nitrogen in the fertilizer used on 
Long Island, this region has used a higher grade of fertilizer than any of the 
other regions. The extra nitrogen has been used to maintain this element 
in view of the heavy draft on it caused by the continuous potato culture. 
The greater use of manure and sod residue in the other regions has furnished 
the nitrogen lacking in the additional fertilizer used. Aside from the 
nitrogen content, the fertilizers used in the four regions have been similar 
in analysis. 

Method of applying fertilizer 
The method of applying fertilizer to potatoes is a question not well 
worked out because it is complicated by, and dependent on, such factors 
as soil type, amount of fertilizer used, and method of planting the crop. 
The question as treated here relates to (1) the depth of applying the 
fertilizer relative to the seed pieces, (2) broadcasting as compared with 
drilling, and (3) time of application relative to time of planting the crop. 
Obviously, fertilizer should be applied at that depth which will afford it 
a constant supply of moisture to make it available to the root system of 
the potato plant. As this depth is less in heavy soils than in light soils, 
both fertilizer and seed are generally applied less deeply in heavy than in 
light soils. Since the root system of the potato plant normally develops 
laterally to a radius of from 18 to 24 inches, the question of depth of appli- 
cation would seem more important than that of whether the application 
should be by drill or broadcast. The question of time of application must 
depend on the availability of the fertilizer used and the seasonal distri- 
bution of rainfall. 



1192 Earle V. Hardenburg 

Taft (1892) reported the comparative yields obtained by placing ferti- 
lizer above and below the seed piece in a year of light rainfall. All plots 
gave a gain of from 14 to 34 bushels per acre in favor of the applications 
below the seed piece. Taft and Coryell (1894) reported on the same 
test covering three years and using complete fertilizer on three varieties. 
The results were all in favor of the application of fertilizer below the seed 
piece, the gain being from 25 to 40 bushels per acre. Munson (1894) 
compared the relative efficiency of applying fertilizer by the Rural-New- 
Yorker trench system, in which the fertilizer is placed in mellow earth two 
inches above the seed, with the method of applying it to the surface and 
harrowing in. Not enough difference in yield was obtained to pay for 
the e'xtra la])or of making the trench required in the former method. 

Rane and Hall (1904), replicating plots three times, compared yields 
from fertilizer applied above and below the seed, both with and without 
the use of stable manure. They obtained in all cases an average difference 
of 18 bushels per acre in favor of the shallow applications. No mention 
was made of the rainfall available that year. 

Van Slyke (1895), at the New York station, compared potato yields 
grown under 1000, 1500, and 2000 pounds of fertilizer per acre, respec- 
tively, applied both broadcast and in the drill row. In all cases in which 
1500 pounds or less was used, the drill-row applications gave the better 
yield by about 10 bushels per acre. When 2000 pounds was applied, there 
was a difference of 17.5 bushels per acre in favor of broadcasting. This 
difference was probably due to a slight injury to the seed pieces caused 
by contact with the fertilizer applied in the drill row, for the stand in the 
latter case was rather uneven. Rane and Hall (1904), using 1500 pounds 
of fertilizer per acre, compared the yields obtained by applying all in the 
hill with those from applying half in the hill and half broadcast. No 
check plots, and only three plots altogether, were used, but a small yield 
favoring the half-and-half method was obtained. The gain, however, 
was due to a larger yield of culls under this method. Hall (1905), in 
reporting the experience of the Rothamsted station, stated that phosphoric 
acid and potash should generally be applied in drills, but that kainit 
should be applied broadcast. Jordan and Sirrine (1910) compared these 
two methods of application at three points on Long Island during the years 
1905 to 1908, inclusive. Altho the differences were small in all cases, 
there was an average gain of 3 bushels per acre in favor of the drill method. 
Applications of 500, 1000, and 1500 pounds, respectively, were compared 
under each method. Woods (1917), using 1000 pounds and 1500 pounds 
of fertilizer, respectively, all broadcast, all drilled, and a part usecl either 
way with the remainder applied after the crop was up, found differences 
favoring the drill method but no greater than might be expected as within 
experimental error. The greatest average difference between the two 
methods, thru the years 1914 to 1916, inclusive, was 6 barrels in favor 



A Study of Factors Influencing the Yield of Potatoes 1193 

of drilling. Woods concluded that nothing is to be gained by the practice 
commonly followed in Maine, of applying some fertilizer along the row 
at the first cultivation, for this method is less convenient and apparently 
no more efficient than applying all the fertilizer in the row at planting time. 

Much variation in t*he method of applying fertilizer has been observed 
in the surveyed areas. Wherever machine planters were used, the ferti- 
lizer was generally applied with these. On Long Island, however, where 
98 per cent of the crop was planted by machine, nearly forty per cent of the 
growers applied the fertilizer broadcast, using a grain drill or a lime sower 
before planting. Tables included in the study of this factor show that 
most of the fertilizer not applied thru the planter was applied broadcast 
before planting. Generally this means an application only a few days 
prior to planting the crop. 

Without exception, on Long Island a higher average yield resulted from 
the broadcasting of fertilizer before planting (table 29) . This difference in 
favor of broadcasting is in part due to the greater quantity of seed usually 
planted when this method is used. But the difference is sufficient to be 
significant. Furthermore, the growers in the first fertilizer group who 
broadcast the fertilizer, used less seed than did those who apphed the 
fertilizer in the drill row. Apparently the average of nearly a ton of 
fertilizer per acre used in this region in 1912, was more efficient when broad- 
cast than when drilled. 

There are rather too few farms included in each of the groups for Steuben 
County (table 30) to allow any definite conclusions to be drawn. The 
differences in yield apparently clue to difference in the method of fertilizer 
application, are all probably due mainly to the indicated difference in the 
amount of seed planted. This leads to the conclusion that for Steuben 
County, when as little as the average of 270 pounds of fertilizer per acre 
is used, it is fully as efficient to apply it all in the drill row as to broadcast 
it either just before or just after planting. 

Altho the differences in yield between the two methods employed in 
Monroe County were small, they are consistent thruout (table 31). 
Usually, less seed was planted per acre by those broadcasting fertilizer 
before planting than was used by those in the other group, yet the yields 
favor the method of broadcasting. The writer is unable to reconcile 
this conclusion with that for Steuben County. Whether the exception 
here favoring broadcasting when an average of only 406 pounds of fertilizer 
per acre was used, is due to seasonal rainfall conditions, is purely conjecture 
which can be settled only by controlled experiments over a protracted 
period, 

A study of table 32, weighing the influence of the amount of seed and the 
value of the fertilizer used in Franklin and Clinton Counties,^ indicates 
that here, as in Monroe County, the broadcasting of the fertilizer proved 
more efficient in 1913 than the application of it in the drill row. It is of 



1194 



Earle V. Hardenburg 





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A Study of Factors Ixflvexcixg the Yield of Potatoes 119." 



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1196 



Earle V. Hardenburg 



interest to note that more than half of the 211 growers hsted here apphed 
their fertihzer by the broadcasting method. 

The study of the methods of applying fertilizer, as treated in this paper, 
does not allow any definite conclusions to be drawn. The question is 
apparently one of local application, probably depending on such factors 
as seasonal rainfall, amount of fertilizer used, and soil type, as previously 

Use and influence of lime on potato kmd 

Lime has been given little prominence in use either as a plant food or 
as a soil amendment for potatoes. This is due to the fact that, being an 
alkaline agent, its use is conducive to the development of common scab 
{Actinoviyces chromogenus) on potato tubers whenever the causal organism 
is present in the soil or introduced on the seed tubers. Therefore lime 
is usually applied in the rotation as far removed from the potato crop as 
is possible, while its major benefits to this crop, in the improvement of 
soil texture and the growth of legumes, are as well accomplished. Wheeler 
and Adams (1909) reported an increase in the proportion of tubers of mer- 
chantable size from the use of lime. There seems to be little or no con- 
clusive evidence available that lime has increased the yield of potatoes 
except indirectly thru the benefits just mentioned. 

In spite of the fact that lime is advised for most potato farms outside 
of the surveyed areas of Long Island and Monroe County, very few growers 
reported its use in the rotation which they were using at the time when 
the survey was made. A summary of the use of Imie and its place in the 
rotation followed in the surveyed regions is given in table 33: 

TABLE 33. Use of Lime, and Its Place in the Four Areas Surveyed 



Region 




Average number 

of years 

removed from 

potatoes 



Long Island, 1912 

Steuben County, 1912 

Monroe County, 1913 

Franklin and Clinton Counties, 1913 



3.4 
3.1 
3.0 
3.7 



Very few growers apply lime regularly in their rotation. The commoner 
practice is to use it only when necessity demands it as a means of producing 
legumes. On Long Island, where potatoes are grown for so many suc- 
cessive seasons on the same land, it is unsafe to use lime at all. The number 
of years from the potato crop that hme is applied, indicated in table 33, 
shows the consistent effort of the growers to apply it as far from potatoes 
as is possible, in order to avoid scab. 



A Study of Factors Influencing the Yield of Potatoes 1197 

ADAPTATION AND YIELD OF VARIETIES 

The crop survey offers one of the best means of determining the relative 
merits of potato varieties for a given locahty. Too often the experiment 
stations have made generaHzed recommendations solely on the basis of 
the performance of a few strains tested for only a few years at the station 
grounds. A correct knowledgie of the adaptabihty of various types and 
varieties to given soil and climatic conditions can be obtained only by 
cooperative controlled tests under varying conditions, or by a crop survey of 
the performance of the varieties growing over a wide area with diverse condi- 
tions. Nearly every state experiment station in the United States has at 
some time conducted a yield test of potato varieties, the results of which are 
to be found in the published literature. These results are in most cases of 
very local significance and pertain only to the strains of seed that were 
available for the test. Because of the wide variation in yield of the dif- 
ferent strains of a given variety, no absolute recommendations for any 
variety should be made on the basis of such tests. A comparison by survey 
methods of the average yields of strains of the varieties within a region, 
furnishes the best criterion of the merits of such varieties for that region. 
Stuart (1915) has classified the standard American varieties into groups 
containing varieties similar in tuber and foliage characters. It is now well 
known that the varieties within each group conform fairly closely to one 
another in their adaptation to specific soil and climatic conditions. This 
has made it possible to determine the type or group of varieties best adapted 
to certain regions. It remains, then, only to choose high-yielding strains 
of standard varieties within this group. The status of varieties within 
each of the surveyed areas has been studied on this basis. Varieties and 
types have been tabulated in the order of their extent of production in 
each region. 

Potato varieties on Long Island 

Of the four regions surveyed, Long Island presented the greatest varietal 
standardization by growing the fewest varieties and the fewest types. 
Growers in this region are convinced that varieties of the Rural -group 
yield less, are poorer in quality, and are less popular in the New York 
market, than varieties of the Green Mountain, or white-sprout, type. 
Generally speaking, for the medium late crop, only varieties of the Green 
Mountain group are raised on Long Island, and the early varieties for 
this region are chosen from the Cobbler, the Early Ohio, the Rose, and 
the Triumph groups (table 34). 

Altho Green Mountain was only one of several varieties of this group 
grown in the three years from 1911 to 1913 inclusive, its popularity is shown 
by the fact that two-thirds of the average total acreage during this period 
was given to this variety. Irish Cobbler was the leading early variety 
produced, and most of the acreage of this variety was grown in Nassau 



1198 



Earle V. Hardenburg 



TABLE 34. Varieties Grown on 330 Long Island Farms in 1911, 1912, and 1913 



Variety 



Color of 
sprout 



Average 
number of 
farms 
raising 
variety in 
1911, 1912, 
and 1913 



Average 
yield per 
acre in 
1911 and 

1912 
(bushels) 



Per cent of 

total 

acreage 

grown in 

1911, 1912, 
and 1913 



Green Mountain. 

Irish Cobbler 

Carman No. 1 . . . 

Delaware 

Mills Pride 

Uncle Sam 

Early Ohio 

Norcross 

World's Fair . . . . 
Genesee Seedling 

Rose 

Bliss Triumph . . . 

Early Rose 

Bagley 



White 
Pink.. 
White 
White 
White 
Blue.. 
Pink.. 
White 
White 
White 
Pink . 
Pink. 
Pink. 
White 



200.7 

119.7 

34.0 

19.3 

16.3 

9.7 

9.7 

8.7 

3.7 

5.3 

5.7 

13.0 

7.0 

4.3 



180 

169 

189 

210 

164 

220 

216 

212.1 

185.8 

248.1 

172.8 

126.9 

104.5 

126.2 



66.0 
13.0 
10.0 
3.0 
2.0 
1.6 
1.6 
1.0 
0.5 
0.3 
0.3 
0.3 
0.2 
0.2 



County. A summary of the varieties belonging to each group, as classi- 
fied by Stuart (1915), is given in table 35: 

TABLE 35. Summary of Types on 330 Long Island Farms in 1911 and 1912 



Type 



Per cent 

of total 

acreage 

in 

1911 



Per cent 

of total 

acreage 

in 

1912 



Average 
jneld 

per acre 

in 

1911 

(bushels) 



Average 


Average 


yield 


amount 


per acre 


of seed 


in 


used in 


1912 


1912 


(bushels) 


(bushels) 



Average 

value 

of 

manure 

and 
fertilizer 
in 1912 



Green .Moimtain 

Cobbler 

Triumph 

Early Ohio 

Rose 

Rural , 



186.6 
189.0 

i99'6' 
166.8 

227.7 



179.7 
157.2 
128.6 
231.5 
123.6 
216.2 



12.9 
12.2 
11.4 
12.3 
13.4 
10.1 



$32.74 
32.00 
28.71 
44.99 
38.72 
27.66 



Since the Green Mountain group is the only one of importance in this 
region, no comparison of relative merits is made between the types. 
Because most of the Early Ohio acreage was produced near or at Orient 
Point, under high fertilization and with ideal moisture conditions, its 
high average yield must be discounted when compared to that of the 
Cobbler group. Owing to its high average yield and its white skin, 
Cobbler has proved to be the best early variety for this section. 



A Study of Factors Influencing the Yield of Potatoes 1199 

Potato varieties in Steuben County 
In contrast to Long; Island, Steuben County showed the least standard- 
ization of varieties of the four regions. The thirty-five varieties listed in 
table 36 do not represent all that were found in the region, but only those 
comprising an average of at least 0.1 per cent of the total acreage for three 
years. 

TABLE 36. Varieties on 360 Steuben County Farms in 1911, 1912, and 1913 



"Variety 



Color of 
sprout 



Average 
number of 
farms 
raising 
variety in 
1911, 1912, 
and 1913 



Average 
yield per 
acre in 
1911 and 

1912 
(bushels) 



Per cent of 
total 



grown m 
1911, 1912, 
and 1913 



Number 9 

Ruloff 

Spaldings Rose 4 

White Pearl 

Sir Walter Raleigh 

Gold Coin 

Dooley 

Carman No. 3 

White Giant 

State of Wisconsin 

Rural New Yorker No. 2 

Green Mountain 

McKinley 

Pan American 

White Granger 

Pearhne 

German Queen 

Planet 

MiUion Dollar 

Early Manistee 

Uncle Sam 

Charles Downing 

American Banner 

Goldstein 

Admiral Dewey 

California 

White Mammoth 

Knoxall 

Carlisle 

Norcross 

Ward's Seedling 

Scotch Mane 

Mix Best 

Early Burpee 

Clustic Beauty 



Blue.. 

White 

Pink.. 

Blue. . 

Blue. . 

White 

Blue. 

Blue . . 

Blue.. 

White 

Blue. . 

White 

Blue.. 

Blue.. 

Blue.. 

Blue . . 

Pink.. 

Blue . . 

Blue.. 

Pink . . 

Blue.. 

White 

Blue.. 

Blue.. 

Blue.. 

White 

White 

Blue.. 

Blue. . 

White 

Blue.. 

Pink.. 

Blue.. 

Pink.. 

White 



76.7 
41.3 
66.6 
20.7 
16.0 
21.0 
15 3 
15.3 
13.0 
12.0 
7.7 
7.3 
8.0 
4.0 
6.3 
4.0 
4.7 
3.7 
3.0 
5.7 
3.0 
3 
2.7 
,7 
.7 
,7 

,7 

3 
2.7 
2.3 
2.0 
2.0 
0.7 



143 5 

126.5 

139.0 

148.5 

156.8 

135.0 

148.8 

149.5 

135. 

134. 

134. 

115. 

142. 

121 

147. 

114. 

154. 

126.8 

118.7 

163.7 

134.0 

118.2 

127.6 

118.0 

167.2 

135.6 

133.8 

159.6 

156.0 

143.0 

136.4 

127.0 

168.9 

108.3 

106.2 



22.6 
12.3 
11.2 
6.6 
4.7 
4.7 
4.5 
4.2 
4.2 
3.1 
2.6 
1.8 
1.7 
1.4 
1.4 
1.3 
1.1 
1.0 
1.0 
0.9 
0.9 
0.8 
0.8 
0.7 
0.7 
0.7 
0.6 
0.5 
0.5 
0.4 
0.3 
0.3 
0.2 
0.1 
0.1 



1200 



Earle V. Hardenburg 



It is significant that the three most popular varieties of this region, repre- 
senting nearly half of the average total acreage during 1911 to 1913 inclu- 
sive, are each of a distinct type. Yet each may have its proper place in 
Steuben County farming. Number 9, representing a high-yielding strain 
selected from Rural New Yorker No. 2, heads the list in table 36 and is an 
ideal blue-sprout variety, adapted to the heavy soils and narrow-valley farms 
of this I'egion. Spaldings Rose 4, a medium early variety of the pink- 
sprout type, is profitably raised for a special seed trade with the Hastings 
potato section of Florida. Ruloff is a variety of the Green Mountain type 
which is well adapted to the lighter soils of the northern part of the county. 
Altho there may be this apparent justification for diversity of type, there 
is surely no justification for so many varieties. Among the more popular 
varieties listed in the table, such standard varieties as Sir Walter Raleigh 
and Carman No. 3 would, on the basis of yield, appear to justify their more 
exclusive use in this region. The average yield of the more popular 
standard white-sprout varieties in this list is considerably inferior to 
that of the Rural varieties, which apparently indicates that, in general, 
this type is not so well adapted here as is that represented by Number 9. 

A comparison of the types produced in this region is shown in table 37: 

TABLE 37. Summary of Types on 360 Steuben County Farms in 1911 and 1912 



1 

1 Per cent 
, of total 
Type acreage 
in 
1 1911 

1 


Per cent 

of total 

acreage 

in 

1912 


Average 
yield 

per acre 
in 
1911 

(bushels) 


Average 
yield 

per acre 
in 
1912 

(bushels) 


Average 
amount 
of seed 
used in 

1912 
(bushels) 


Average 
value of 

manure 

and 
fertilizer 

in 1912 


Rural 


76 
14 

9 

1 


75 

15 

9 

1 


138 
126.3 
113.8 
116.7 


142.4 
123.1 
142.2 
194.4 


8.8 
15.5 
9.7 
9.8 


f 8.90 




13.57 


Rose 


8.89 


Hebron 


12.82 







In both 1911 and 1912, the Rural group of varieties outyielded those of 
the Green Mountain type by an average difference of 12 and 19 bushels 
per acre, respectively, in spite of the fact that in both years they were 
grown with considerably less seed and fertilizer. As is shown later, in 
table 42, a part of this difference was due to a greater average loss per 
acre in the unharvested yield, due to late blight rot, in the Green Mountain 
varieties. It therefore appears certain that the Rural type of potato is 
better adapted to the prevailing conditions of this region. 



A Study of Factors Influencing the Yield of Potatoes 1201 

Potato varieties in Monroe County 
Altho a very large number of varieties were grown in Monroe County 
during the years 1912 to 1914, inclusive, it is seen in table 38 that the 

TABLE 38. Varieties on 300 Monroe County Farms in 1912, 1913, and 1914 



Variety 



Color of 
sprout 



Average 
number of 
farms 
raising 
variety in 
1912, 1913, 
and 1914 



Average 
yield per 
acre in 
1912 and 

1913 
(bushels) 



Per cent of 
total 
acreage 
grown in 
1912, 1913, 
and 1914 



Sir Walter Ruileigh . . . . 

Carman No. 3 

Number 9 

Peerless Jr 

White Giant 

MilHpn Dollar 

Perfection 

World's Wonder 

White Flyers 

White Grant 

Rural New Yorker No 

Gold Coin 

American Giant 

Granger 

Twentieth Century . . . 

Isle of Jersey 

Hundred Fold 

Irish Cobbler 

Number 6 

Pan American 

McKinley 

Green Mountain 

Early Michigan 

Livingston 

American Banner 

Number 8 



Blue. 

Blue. 

Blue. 

Blue. 

Blue. 

Blue. 

Blue. 

Blue. 

? 

Blue . 

Blue . 

White 

White 

Blue.. 

Blue.. 

Blue.. 

? 

Pink.. 

Blue. 

Blue . , 

Blue.. 

White 

Pink.. 

Pink.. 

Blue.. 

Blue . . 



59.3 

37 3 

45 3 

21.0 

22.3 

21.0 

17.0 

22.3 

10.0 

14.0 

7.7 

3 3 

6.3 

3 





7 



5 
6 
3 
4 
11.7 



103.9 
128.2 
1?5.6 
124.5 
129.9 
147.0 
144.1 
138.9 
119.2 
130.2 
124.1 
111.0 
133.4 
109.2 
164.9 
110.8 
141.2 
124.6 
146.5 
138.5 
156.5 
174.9 
115.0 
90.6 
153.7 
150.8 



20.7 
13.5 
12.3 
8.3 
6.8 
6.1 
5.5 
4.5 
2.6 
2.4 
2.3 



1.6 
1.4 
1.4 
1.3 
1.2 
1.2 
1.2 
1.2 
1.1 
0.9 
0.8 
0.5 
0.5 
0.4 
0.3 



prevaihng type was that of the Rural group. Nearly half of the average 
total acreage of this region during the years 1912 to 1914, inclusive, was 
planted to the three standard blue-sprout varieties. Sir Walter Raleigh, 
Carman No. 3, and Number 9. Altho the three-years average yield for these 
varieties was slightly less than the average yield for the region in 1913, 
it would still seem desirable, for the sake of standardization, to sedect high- 
yielding strains from, and to retain, these few varieties to the exclusion of 
most of the other varieties of the Rural type Hsted in table 38. It is note- 
worthy that of the twenty-six varieties listed, only three are of the Green 



1202 



Earle V. Hardenburg 



Mountain type. The relatively light seasonal rainfall and the heavy 
soils of the Dunkirk and Ontario series have resulted in the survival of 
Rural varieties at the expense of other types. Here, as on Long Island, 
Irish Cobbler was found to be the leading early variety. 
The status of varietal types in this region is summarized in table 39: 

TABLE 39. Summary of Types on 300 Monroe County Farms in 1912 and 1913 



Type 


Per cent 

of total 

acreage 

in 

1912 


Per cent 

of total 

acreage 

in 

1913 


Average 
yield 

per acre 
in 
1912 

(bushels) 


Average 
yield 

per acre 
in 
1913 

(bushels) 


Average 
amount 
of seed 
used in 
1913 

(bushels) 


Average 
value of 
manure 

and 
fertiUzer 
in 1913 


Rural 

Green Mountain 


94.0 
3.4 
1.0 
1.0 
0.3 
0.3 


94.0 
3.0 
1.0 
0.5 
O.S 
0.7 


141.4 
153.3 
135.9 
121.0 
128.6 
121.4 


125.0 
109.4 
117.1 
138.8 
80.0 
100.0 


12.8 
14.3 
11.6 
14.5 
10.6 
11.1 


$11.48 
10.97 


Cobbler 

Hebrcn 


12.75 
9.65 


Rose 


4.40 




5.56 







The year 1913 was one of low seasonal rainfall in Monroe County, 
and the crop suffered from the drought. As shown in table 39, varieties 
of the Green Mountain group yielded, in that year, an average of about 
15 bushels per acre less than those of the Rural type, in spite of the use of 
more seed and about the same amount of fertilizer. This is further evi- 
dence that varieties of the Green Mountain group, which set tubers earlier 
than do those of the Rural group, suffer the effects of reaching their 
critical growth period during the drought season of midsummer in Monroe 
County. 

Potato varieties in Franklin and Clinton Counties 

Altho more varieties are grown in Franklin and Clinton Counties than 
on Long Island, this region is similar to the Long Island area in that 
nearly all the varieties were found to be of the Green Mountain type, 
as is shown in table 40. A' notable absence of early varieties was found 
among those grown from 1912 to 1914, inclusive. This may be explained 
in general by the fact that the possibilities for profitable yields are much 
greater in the main crop varieties. 

The four Green Mountain varieties hsted at the head of table 40 — White 
Beauty, Selfic Beauty, World's Fair, and Immense — comprised more than 
half of the average total acreage of this region during the three years con- 
cerned. Type has become well standardized here, as the list shows only 
four varieties of the Rural, or blue-sprout type, the remainder all being 
of the Green Mountain, or white-sprout, type. While these four Rural 
varieties are standard varieties, their average yield per acre and extent of 



A Study of Factors Influencing the Yield of Potatoes 1203 



TABLE 40. Varieties on 300 Franklin and Clinton County Farms in 1912, 1913, 

AND 1914 



Variety 



Color of 
sprout 



Average 
number of 
farms 
raising 
variety in 
1912, 1913, 
and 1914 



Average 

yield per 

acre in 

1912 and 

1913 
(bushels) 



Per cent of 
total 



grown m 
1912, 1913, 
and 1914 



White Beauty 

Selfic Beauty 

World's Fair 

Immense 

White Mountain 

Green Mountain 

Jumbo 

White Lady 

Number 9 

Mill's Prize , 

Carman No. 1 

National 

Rural New Yorker No. 2 . 

Lincoln 

Scott 

Mountain King 

Eggswaire 

Carman No. 2 

Success 

International 

Gold Coin 

Silver Dollar 

Carman No. 3 



White . 
White. 
White. 
White . 
White. 
White. 
White. 
White. 
Blue. . . 
White. 
White . 
White . 
Blue. . 
White . 
? 

White. 
White . 
Blue. . 



White. 
White . 
White . 
Blue.. 



47.3 

39.3 

32.3 

17.7 

20.3 

18.7 

14.0 

8.7 

11.3 

7.7 

10.7 

6.7 

6.3 

6.3 

4.7 

5.3 

5.0 

5.3 

3.7 

3.0 

2.0 

4.7 

1.7 



198.1 

200.7 

179,9 

154.5 

199.1 

179.5 

17B.8 

197.9 

168.9 

189.9 

204.5 

184.8 

135.6 

221.8 

160.6 

199.7 

165.6 

191.9 

169.9 

197.3 

147.7 

187.4 

184.0 



16.4 
15.0 
12.3 
7.1 
6.7 
6.6 
4.7 
4.1 
4.0 
3.0 
3.0 
2.4 
2.0 
1.9 
1.8 
1.7 
1.7 
1.6 
1.2 
0.9 
0.7 
0.7 
0.5 



production do not seem to justify their competition with the Green Moun- 
tain type A comparison of these two types for the region in 1912 and 
1913 is shown in table 41. The averages for 1912 and 1913 show that with 

TABLE 41. Summary of Types on 300 Franklin and Clinton County Farms in 1912 

AND 1913 



Type 


Per cent 

of total 

acreage 

in 

1912 


Per cent 

of total 

acreage 

in 

1913 


Average 
yield 

per acre 

in 

1912 

(bushelsl 


Average 
yield 

per acre 

in 

1913 

(bushels) 


Average 
amount 
of seed 
used in 
1913 

(bushels) 


Average 
value of 
manure 

and 
fertiUzer 
in 1913 


Green Mountain 


86 
14 


92 

8 


194.5 
168.9 


183.8 
164.9 


12.0 
13.1 


$13 44 


Rural 


14 42 







1204 



Earle V. Hardenburg 




A Study of Factors Influencing the Yield of Potatoes 1205 

a bushel of seed less and a dollar's worth less of fertilizer per acre, the 
varieties of the Green Mountain group yielded approximately 26 and 19 
bushels per acre more, respectively, than did the Rural varieties. Under 
the cool climatic and the good soil conditions of this region, therefore, 
the Oreen Mountain type of potato is the more profitable. 



Summary of varieties in all regions 

A comparison of the principal potato groups produced in all four regions 
during the years for which survey data were obtained, is shown in table 
42. It should be understood that no specific recommendations for a given 
region can be made on the basis of the comparisons drawn in this table. 
Certain facts of interest, however, are evident. On the average, the 
Green Mountain type is grown under more favorable climatic and soil 
conditions than the other types, with more seed and more manure and 
fertilizer per acre. Therefore, for the State as a whole, the Green Mountain 
varieties have yielded more than have those of the Rural type. The table 
shows that in the blight epiphytotic of 1912 in Steuben County, the rotting 
of the white-sprout varieties in the field exceeded that of the blue- sprout 
varieties by about 24 bushels per acre. For practically the same reasons 
the Cobbler type has outjdelded the Rose as an early potato. The Early 
Ohio owes its high average jdeld in 1912 to the large amount of seed and 
fertilizer used. 

SOURCE OF SEED 

In the mind of the average grower, the source of his potato seed is of 
small concern unless of necessity he is compelled to periodically change 
his seed stock by obtaining it outside his home county. The only section 
in New York where this is the case is Long Island. In table 43 are shown 
the sources from which the seed supply was obtained for each of the surveyed 
regions in 1912 and 1913. 

TABLE 43. Source of Seed in the Four Regions Surveyed, in 1912 and 1913 



Region 


Farms raising their 
own seed 


Farms raising part 

and buying part of 

their seed 


Farms buying all their 

seed 




Number 


Per cent 


Number 


Per cent 


Number 


Per cent 


Long Island 

Steuben County .... 

Monroe County .... 

Franklin and Clinton 

Counties 


9 
358 

248 

215 


2,7 

99.4 

82.7 

71.7 


151 
2 

38 
50 


45.8 
0.6 
12.6 

16.6 


170 

14 

35 


51.5 
0.0 
4.7 

11.7 







1206 Earle V. Hardenburg 

For many years, the Long Island growers have been getting most of 
their seed from Maine. In recent years, the decreasing qiiahty of Maine 
seed has resulted in the use of some seed from Vermont and New York. 
Seed for the other three regions is almost entirely used within the county 
where it is grown. Occasionally there is an exchange of seed between 
growers within the neighborhood. Long Island growers have learned 
that it is not profitable to use, as seed, stock that has been grown on Long 
Island for more than one year. An experimental plot at Southampton 
is shown in figure 131 (page 1158), which demonstrates the difference in 
results to be expected between new stock from Maine, and Maine stock 
grown for one year on Long Island. The 45.8 per cent of growers on Long 
Island using part home-grown seed and part bought seed, shown in table 
43, represent the extent to which one-year Long Island stock originally 
imported from Maine was used in 1912. Most of the seed stock from Maine 
is purchased in the fall to be shipped in the very early spring, since storage 
facihties on Long Island are very meager and the crop is planted late in 
March or early in April. The seed stock of the other three regions is 
in most cases stored at home along with the bulk of the harvested crop. 

The necessity of a change of seed on Long Island is due to several factors. 
The abnormally long period between harvest and planting, much of which 
includes the warm or hot temperatures of late summer and early fall, is 
not favorable to potato storage. The soil temperature of this region during 
the later growing season is apparently so high as to seriously reduce the 
vigor of the stock for seed, in spite of the high average yields obtained. 
The problem is therefore one of soil, of growing-season and storage tem- 
peratures, and of length of storage season as influencing the condition of 
the seed at planting time. 

Emerson (1914) compared yields from seed cultivated for some time 
in Nebraska, with those from seed raised under straw mulch and from seed 
recently introduced from the Red River Valley of North Dakota. He 
found that, whereas the cultivated seed of Nebraska rapidly deteriorated 
under hot growing-season temperatures, by mulching with straw between 
planting and blossoming time he was able to so reduce the soil temperature 
as to maintain vigor and obtain practically as good yields from seed so 
raised as from seed just introduced. Stuart (1913 a) studied the influence 
of environment on seed by introducing seed of thirteen English varieties 
of identical origin from both England and Scotland, and growing it con- 
tinuously in Vermont for six years. The average increase in yield of the 
Scotch seed over that of the seed from England varied from 10.9 to 2713.9 
per cent. Results similarly striking were obtained by Macoun (1905) in 
four varieties grown over a period of twenty years at Ottawa. He had 
practiced seed selection each year for twelve years and had thus been able 
to maintain the original yield of the stock. Four years of adverse con- 
ditions followed, 'during which the yield of each variety decreased decidedly. 



A Study of Factors Influencing the Yield of Potatoes 1207 

Seed of these same varieties, introduced during the last four unfavorable 
years from Nappan, Nova Scotia, and subjected to the same unfavorable 
conditions, maintained its yield much better, showing that the vigor of 
northern-grown seed enabled it to withstand adversity better than home- 
grown seed similarly treated. Stone (1905) reported an experiment by 
Fraser in which tubers that had been stored in a cool cellar until May 1 
were taken out and stored for thirty-six days under four different con- 
ditions. Yields from seed stored in a dark cellar at from 50° to 60° F., 
in a coldframe at 80°, at a Vjarn window at out-of-door temperatures, and 
in a greenhouse at from 70° to 90°, showed about equally good results 
from the coldframe and the barn-window storage. The seed stored in the 
dark cellar gave decidedly inferior average yields, showing that moderate 
light and temperature for from four to six weeks before planting improves 
production over the usual method of dark-cellar storage up to planting 
time. 

The potato crop of Maine, Vermont, and northern New York is almost 
invariably harvested before the maturity of the plants. The vines are 
usually killed by frost. Therefore the use of northern-grown seed for 
Long Island means the use of immature seed; and, since immature seed 
is closely associated with the dormancy, or rest period, of the potato 
tubers, this question also is concerned. According to Appleman (1918), 
the rest period varies with the variety but is fairly constant within each 
variety. Appleman (1912) has shown that three processes go on in 
potato tubers during the rest period: (1) respiration, or the consumption 
of sugar by reversion to carbon dioxide and water; (2) conversion of starch 
to sugar by diastase; and (3) change of the sugar back to starch. Since 
these after-ripening processes are greatly influenced by temperature, it 
follows that storage conditions have much to do with the condition of the 
seed tubers when they are removed from storage for planting. The value 
of seed harvested in an immature condition, which has been shown by 
the experiments of Macoun (1905), Shepperd and Churchill (1911), Stuart 
(1913 b), Zavitz (1916), Ballou (1910), and Gourley (1910), is due prin- 
cipally to the fact that, the seed being immature, the after-ripening 
processes leave it in a less devitalized condition than that of seed that 
has entered storage fully matured. The symptom of curled skin so 
conamon at harvest time on northern-grown potatoes indicates a lesser 
degree of suberization of the epidermis than occurs in mature tubers. 
Appleman (1914 and 1918) has shown how the rest period may be shortened 
or broken, at almost any time, by the use of anaesthetics or of oxidizing 
agents to facilitate increased oxygen absorption. He further showed 
(1918) how the rest period of the southern second-crop seed may be short- 
ened by harvesting the seed immature, spreading it on the ground, and 
covering it with excelsior or burlap to prevent suberization. 



1208 



Earle V. Hardenburg 



SUN-SPROUTING OF SEED 

The practice of sun-sprouting seed is one which, tho recommended for 
many years by experiment stations, has been very Httle practiced by 
potato growers. It requires the bringing of the seed stock from dark 
cellars into a place of moderate light and higher temperatures for a period 
of from four to six weeks prior to planting. The main objects are to 
improve the stands and increase the yields by (1) the development of 
short, thick, green sprouts on which tuber-bearing rhizomes develop close 
together, (2) the opportunity to rogue diseased and otherwise inferior 
seed, and (3) increasing the earliness thru the starting of healthy growth 
before planting. Flagg, Towar, and Tucker (1896), in Rhode Island, 
using duplicate plots and harvesting at two different dates, obtained 
increased yields from sprouted seed ranging from .32 to 54 bushels per 
acre. Fraser (1912) sun-sprouted seed of the varieties Sir Walter Raleigh 
and Carman No. 3 for thirty-six days prior to planting, and obtained 
increases in yield ranging from 0.9 to 73.7 per cent. Hutcheson and 
Wolfe (1917), in a two-years comparison, obtained a difference in market- 
able yield of about 8 bushels per acre in favor of sun-sprouted seed. 

The extent to which sun-sprouting is practiced in the areas surveyed is 
shown in table 44. Altho earliness is much desired by Long Island, growers, 

TABLE 44. Groweks'Who Sun-sprouted Their Seed in the Four Regions Surveyed 



Long 

Island, 

1912 



Steuben 

County, 

1912 



Monroe 

County, 

1913 



Franklin 

and 
Clinton 
Counties, 

1913 



Number of growers. 
Per cent of growers . 



166 
5.5 



no one was found who sun-sprouted seed for the 1912 crop. Much care is 
used in choosing seed at the time of its purchase in the North. The several 
days required for cutting the large amount of seed handled by the average 
grower in this region affords some opportunity for sprout development 
in the meantime. Furthermore, since nearly all of the Long Island crop 
is planted by machine, care would be necessary that none of the sprouts 
so formed would be knocked off in going thru the planter. 

The 4 per cent of growers practicing sun-sprouting in Steuben County 
in 1912 furnishes too small a number to study the influence of sun-sprouting 
on yield in this region. 

The influence of sun-sprouting on yield in Monroe County in 1913 is 
shown in table 45. The difference of about 8 bushels per acre in favor of 



A Study of Factors Influencing the Yield of Potatoes 1209 
TABLE 45. Relation of Sun-sprouting to Yield on 166 Monroe County Farms in 1913 



Treatment 


Number 
of 

farm.s 


Yield 
per acre 
(bushels) 


Average 

amount 

of seed 

used 

(bushels) 


Average 
value of 
manure 

and 
fertilizer 


Not sun-sprouted 

Sun-sprouted 


134 
166 


121.7 
129.5 


12.4 
12.6 


$10.81 
11.64 


Total 


300 
















126.2 


12.5 


$11.28 









the sprouted seed is probably no more than might be due to the increased 
amounts of fertihzer and seed used on these same farnis. Therefore it 
cannot be said, on the basis of this difference in yield, that in 1913 sun- 
sprouting paid for the extra labor involved. 

A similar study of this factor for 40 farms in Franklin and Clinton 
Counties in 1913 is shown in table 46. Here the results of sprouting were 

TABLE 46. > Relation of Sun-sprouting to Yield on 40 Franklin and Clinton County 
Farms in 1913 



'Treatment 


Number 

of 

farms 


Yield 
per acre 
(bushels) 


Average 

amomit 

of seed 

used 

(bushels) 


Average 
value of 
manure 

and 
fertilizer 


Not sun-sprouted 


260 
40 


179.0 
180.6 


11.4 
12.6 


$13.25 


Sun-sprouted 


11.65 






Total 


300 
















179.3 


12.0 


$13.01 









even less marked than in Monroe County. The difference of 1.6 bushels 
per acre in favor of sun-sprouting, while within experimental error, may 
easily be due to the increased amount of seed used by growers in this 
group. The smaller value of fertilizer, however, would partially offset 
the difference in the amount of seed used. 

Tho sun-sprouting apparently is not justified by the results shown for the 
last two regions in 1913, it must not be concluded that this is not< a profit- 
able procedure when it is properly done. It is impossible to determine by 
survey methods the true merits of this phase of potato growing, because 
of the difficulty of taking into account the actual methods followed. 



1210 



Earle V. Hardenburg 



CHEMICAL TREATMENT OF SEED 

The chemical treatment of seed potatoes to rid their surfaces of the organ- 
isms causing common scab (Actinomyces chromogeniis) and rhizoctonia 
(Corticium vaguum) has been sufficiently tested scientifically to warrant its 
practice wherever these diseases occur. Tho such treatments as immersion 
in corrosive sublimate or formaldehyde, or fumigation with formaldehyde 
gas, are not warranted to insure the crop against either of these diseases 
in the following crop, yet they have invariably reduced the infection to a 
profitable extent. Ballou (1910) and Gourley (1910), using duphcate 
plots of untreated seed, seed treated with formalin, and seed fumigated 
with formaldehyde gas, reduced the scab infection from an average of 
58.5 per cent in untreated seed to 16.7 per cent in formalin-treated seed 
and to 18.4 per cent in fumigated seed. The writer (Hardenburg, 1917) 
reported a reduction of rhizoctonia, in the crops of fifty-eight growers in 
New York who used corrosive sublimate, to 1.8 per cent infection as 
compared with 12.7 per cent infection of the crops grown by the remaining 
twenty-two growers considered. He reported a similar reduction of scab 
infection, thru formalin treatment by sixty-two growers, to 7 per cent as 
compared with 10.7 per cent in the crops grown from untreated seed. 

In spite of these tests and the recommendations based on them, a rela- 
tively small proportion of growers in the four surveyed regions treat their 
seed. The percentage doing this in each region is reported in table 47: 

TABLE 47. Per Cent of Growers Treating Seed Chemically in the Four Regions 

Surveyed 



Treatment 


Long 

Island, 

1912 


Steuben 

County, 

1912 


Monroe 

County, 

1913 


Franklin 

and 
Clinton 
Counties, 

1913 


Formalin . 


1.0 
0.0 
1.0 
0.0 


0.003 
0.000 
0.000 
0.000 


7.3 
1.7 
0.0 

3.7 


0.0 


Corrosive sublimate ... 


0.0 


Formaldehyde gas 


0.0 


Sulfur 


0.0 


Total 


2.0 


0.003 


12.7 


0.0 



It has not been possible in this study to correlate the apparent need of 
seed treatment with the actual practice as indicated in this table. This is 
due partly to incomplete data from the four regions, and partly to a lack 
of familiarity with diseases on the part of growers. Such treatment, 
however, is universally recommended because of the attested saving to 
the crop. For the four regions, an average of 8.3 per cent of the growers 
reported scab, and an average of 4.6 per cent reported rhizoctonia, in the 
crop from which these data were taken. 



A Study of Factors Influencing the Yield of Potatoes 1211 

INTERVAL between CUTTING AND PLANTING 

An interval of from one to ten days sometimes elapses between the 
time when seed potatoes are cut and the time when they are planted. 
Weather conditions unsuited to planting after the seed is cut sometimes 
make this delay necessary, while in some sections the large amount of 
seed to be cut makes it seem advisable to cut it several days early in order 
to facilitate the earliest possible planting of the crop. To some extent 
this is the case on Long Island. In a few cases, growers have cut seed 
several days in advance of planting because of an assumed benefit from the 
drying of the cut surface of the seed pieces to be planted. The object of 
the present discussion is to determine the relation of this interval of time 
to the yield. 

Adams (1887), using two varieties in a single-year test, obtained an 
average difference of 26 bushels per acre in favor of planning immediately 
after cutting, between seed cut and planted fresh and seed cut twelve days 
before planting. Green (1888), on the contrary, using three varieties in 
a single-year test, reported increased yields for two varieties from a five- 
days interval, for three varieties from a nine-days interval, and for one 
variety from a twelve-days interval, over the yields obtained by planting 
freshly cut seed. These tests, he reported, agreed with those of Goff, of 
Geneva, who recommended the benefits of drying cut seed for periods not 
exceeding ten days before planting. T. C. Johnson (1912) , tho not reporting 
yields, published cuts of fields planted from freshly cut seed and from seed 
held for ten days after cutting. The outstanding feature of Johnson's 
test of this factor, carried out under carefully controlled conditions, was 
the strikingly poorer stand grown from the stored cut seed. Zavitz (1916), 
in a test covering eight years at the Ontario station, obtained an average 
difference of 8 bushels per acre in favor of planting freshly cut seed rather 
than seed held for only four or five days. Furthermore, he obtained an 
increase of 1 per cent of marketable tubers from the unstored seed. 

As previously stated, the period between cutting and planting is fre- 
quently longer on Long Island than in any of the other three regions 
surveyed. The relation between this interval and the yield is shown in 
table 48. Altho the relation is not clearly apparent, it is evident that as 
the interval is increased, the practice of dusting is also increased. Dusting 
tends to eliminate any of the deleterious effects caused by the drying out 
or heating of seed cut and stored over the longer periods of time. The 
average length of the interval between cutting and planting in this region 
in 1912 was 5.7 days, and more than half of the growers dusted their cut 
seed. 

The average interval between cutting and planting in Steuben County 
being only two days, little correlation between this factor and yield would 
be expected. This is borne out by table 49. Also, here, as on Long Island, 



1212 



Earle V. Hardenburg 



TABLE 48. 



Relation of Interval between Cutting and Planting, to Yield, on 
272 Long Island Farms in 1912 



Interval 

(days) 


Number 
of 

farms 


Yield 
per acre 
(bushels) 


P?r cent 

of 
growers 
dusting 
cut seed 


' Average 
amoimt 
of seed 

used 
(bushels) 


Average 

value 
of manure 

and 
fertiUzer 


Less than 2 . 


39 
33 
52 
32 
13 
43 
60 


161.4 
185.4 
183.5 
171.1 
195.4 
178.4 
177.3 


41 
55 
46 
59 
46 
56 
73 


12.0 
12.8 
12.5 
12.0 
12.5 
12.5 
12.9 


$32 69 


2-3 


31 73 


3-4 


33 33 


4-5 •... 

5-7 


30.45 
32.39 
32 41 




33 53 






Total 


272 




















Average, 5.7 days 




180.0 


57 


12.6 


$32.62 



TABLE 49. 



RelatioiJ of Interval between Cutting and Planting, to Yield, on 
354 Steuben County Farms in 1912 



Interval 

(days) 


Number 

of 

farms 


Yield" 
per acre 
(bushels) 


Per cent 

of 
growers 
dusting 
cut seed 


Average 
amount 
of seed 

used 
(bushels) 


Average 

value 
of manure 

and 
fertiUzer 


Less than 1 


103 

84 
82 
55 
30 


125.0 
145.3 
140.4 
132.4 
149.6 


1^ 

11 
25 

27 


10.0 
10.5 
10.1 
• 9.9 
10.2 


$ 8 65 


1-2 

2-3 

3-5 


10.27 
11.39 
10.21 


5-15 - 


11.62 


Total 


354 




















Average, 2 days 




136.6 


14 


10.1 


$10 17 



dusting was commonest where the mterval between cutting and planting 
was the greatest. This being true, the average yields for each group 
reported in the table appear to vary according to the average amounts of 
seed and fertilizer used, rather than according to the length of the interval 
between cutting and planting. 

The average interval between cutting and planting in Monroe County 
was 2.2 days, as shown in table 50. The range in interval was too small 
to show any marked influence of this factor on yield. In the main, dusting 
was commonest where the interval was the greatest. As in Steuben 



A Study of Factors Influencing the Yield of Potatoes 1213 



TABLE 50. Relation of Interval between Cutting and Planting, to Yield, on 
260 Monroe County Farms in 1913 



Interval 

(days) 


Number 

of 

farms 


Yield 
per acre 
(bushels) 


Per cent 

of 
growers 
dusting 
cut seed 


Average 

amoimt 

of seed 

used 

(bushels) 


Average 

value 
of manure 

and 
fertilizer 


Less than 1 


58 
66 
64 
42 
30 


141.7 
145.3 
121.8 
132.0 
135.2 


7 

21 

22 

. 10 

27 


13.1 
13.0 
12.6 
12.1 
11.6 


111 68 


1-2 

2-3 


13.32 
10 80 


3-4 


10 79 


4 and more 


10.87 


Total 


260 




















Average, 2.2 days 




135.7 


17 


12.6 


$11.66 



County, the amount of seed and fertilizer used was so influential as to 
obscure any slight influence that the factor of the interval between cutting 
and planting might have had. 

Growers in the Franklin and Clinton County areas, like those of Steuben 
and Monroe Counties, aim to plant their seed as quickly as possible after 
cutting. The average interval in 1913 was only two days. Since only 
about ten per cent of the growers held seed as long as four days after cutting, 
no significant relation of this factor to yield was found. However, as 
shown in table 51, the most dusting was done by the growers who held 
their seed the longest. 

TABLE 51. Relation op Interval between Cutting and Planting, to Yield, on 
264 Franklin and Clinton County Farms in 1913 



Interval 

(days) 


Number 

of 

farms 


Yield 
per acre 
(bushels) 


Per cent 

of 
growers 
dusting 
cut seed 


Average 

amoimt 

of seed 

used 

. (bushels) 


Average 

value 
of manure 

and 
fertilizer 


Less than 1 . . 


113 
51 
37 
30 
33 


174.2 
193.1 

178. 7 
173.6 
186.5 


4 
2 
5 

30 


12.2 
12.4 
11 4 
11.6 
12.6 


$13 27 


1-2 


12 42 


2-3 .. . 


13 14 


3-4 . 


12 64 


4 and more 


15 11 


Total 


264 





















Average, 2 days 




180.1 


6 


12.0 


$13.32 



1214 



Earle V. Hardenburg 



DUSTING CUT SEED 

Dusting of cut seed has for its objects the prevention of drying out by- 
undue bleeding of the cut surfaces, and the prevention of heating which 
may occur in cut seed stored in large volume under conditions of poor 
ventilation. Dusting is not commonly practiced except when conditions 
require the storage of large quantities of cut seed for several days before 
planting, as on Long Island in 1912. Stone (1905) compared the yields 
from five varieties cut only one or two days before planting, one lot of 
each variety being dusted with land plaster and the other lot not being 
dusted. Four of these varieties gave increased yields from dusting, 
ranging from 5 to 26 bushels per acre, while the fifth showed a decreased 
yield of 7 bushels. The writer believes that a greater interval between 
cutting and planting would have resulted in a greater increase in yield due 
to dusting. Zavitz (1916) reported on an average of twenty-two tests, 
covering five years, in which yields from undusted freshly cut seed were 
compared with yields from seed treated with land plaster and with slaked 
lime. In all these tests, the seed was planted immediately after cutting 
and dusting. The average yield from the seed treated with plaster was 
23.6 bushels per acre higher than that from the untreated seed, and the 
average yield from the seed treated with lime was 9.8 bushels per acre more 
than that from the untreated seed. In another experiment, in which the 
effects of treating cut seed with road dust, with ground brick, and with 
land plaster, were compared with the results from no treatment, Zavitz 
reported yields of 186, 189, 191, and 179 bushels per acre, respectively. 
Land plaster has been most commonly used as dust because of its cheapness 
and its adhesive qualities. On the basis of all the comparative tests 
reported, it has proved the most efficient. Sulfur and air-slaked lime have 
been used to a lesser extent. The degree to which dusting was practiced 
in the surveyed regions, as related to the length of time the cut seed was 
stored, is shown in table 52, and the extent to which various dust materials 
were used is shown in table 53. Unfortunately, the material used for 



TABLE 52. Relation of Dusting to Length op Storage Period of Cut Seed in the 
Four Regions Surveyed 





Long 

Island, 

1912 


Steuben 

County, 

1912 


Monroe 

County, 

1913 


Franklin 

and 

Clinton 

Counties, 

1913 


Average number of days seed was 


5.7 
57 


2.0 
14 


2.2 
17 


2.G 


Per cent of growers dusting cut seed 


6 



A Study of Factors Influencing the Yield of Potatoes 1215 
TABLE 53. Per Cent of Growers Dusting Seed Who Used Each Material 



Material 


Long 

Island, 

1912 


Steuben 

County, 

1912 


Monroe 

County, 

1913 


Franklin 

and 
Clinton 
Counties, . 

1913 


Land plaster 


49 
43 
1 


3 
4 


72 
4 
2 




22 


20 
16 


6 
2 

56 


11 


Sulfur 


6 




6 




67 







Ashes 





Unnamed 


10 



dusting was not ascertained from all the growers who followed this practice. 
In the cases in which it was not ascertained, it was listed as Unnamed. 
Land plaster was shown to be the material most commonly used, with 
sulfur second. About two-thirds of the growers in Franklin and Clinton 
Counties who dusted, used air-slaked lime, which was not used in any 
other region. Evidently, because of the likelihood that they cause scab, 
neither form of lime has been popular, nor have wood ashes. 

TYPE OF seed 

Probably no other phases of potato culture have received more experi- 
mental attention than those bearing on the relation of type and amount 
of seed planted, to yield. In attempting to correlate type of seed with 
yield, however, the all-important factor of amount of seed used has too 
often been neglected, both in the method of experimentation and in the 
conclusions. This has led to confusion, false conclusions, and a con- 
glomeration of published data of questionable value. To be of real value, 
such tests must take into account both the types of seed used and the 
amount of each planted. The relation of type of seed to yield may be 
treated under the following headings: (1) large as compared with small 
tubers for seed, (2) whole as compared with cut seed, (3) large as compared 
with small seed pieces, and (4) number of eyes. In reviewing the litera- 
ture on each of these points, it has been difficult to reach conclusions, 
because of the confusion, in most cases, of one factor with one or more of 
the others; and very often the amount of seed planted has been entirely 
neglected. 

Large as compared with small tubers for seed 

More than thirty years ago, Adams (1889) compared the yields from 
large, medium, and small whole seed, and found an increase both in total 
and in marketable yield with each increase in size of tubers used. With an 



1216 Earle V. Hardenburg 

equidistant spacing of 38 inches for each type of seed, more per acre of 
the large than of the small type was planted. Aicher (1917) compared 
the yields from three lots of whole seed of a given variety having an average 
tuber weight of 8, 4, and 3 ounces, respectively. Tho Aicher did not state 
the amount of seed per acre used for each lot planted, the sets of each lot 
were planted 16 inches apart in rows 3 feet apart. Aicher reported that 
as the size of the whole seed was increased, the number of stalks per hill 
and the total yield per acre were increased. There was little difference 
in the percentage of marketable yield between the three lots. It must be 
concluded from this that large whole seed is better than small whole seed, 
under equidistance of planting, only because of the greater weight of seed 
used. Welch (1917), in a similar experiment and under similar conditions, 
duplicated Aicher's results almost exactly, except that he obtained a 
decrease in the percentage of marketable yield as the size of the whole 
seed increased. It is clear that the greater yields obtained by Welch 
from the larger whole seed were due primarily to the almost doubled amount 
of seed involved in each increase in size of seed used. Harwood and Holden 
(1893) have brought together the results obtained at the New York, 
Maryland, Tennessee, Kentucky, Louisiana, Wisconsin, and Utah stations, 
in all of which it was shown that in many cases not only the gross but also 
the net yield was greatest from the largest whole seed tubers. However, 
in all cases this increased yield was obtained from the greatly increased 
amount of seed used. Zavitz (1916) selected continuously, for eleven 
years, seed of small unmarketable, small marketable, medium marketable, 
and large marketable, whole seed tubers, and planted each lot in duplicate 
plots. With but one slight exception in the eleven years, his average 
marketable yield from the four types of seed showed an increase with each 
increase in size of seed used. The average yields per acre from the 
smallest to the largest seed, for the eleven years, were 105, 145, 181, and 
203 bushels, respectively. Zavitz credits these differences in yield to the 
difference in the weight of .the seed tubers, that is, to the difference in the 
amount of seed planted per acre. Plumb (1890) planted whole seed of 
Early Rose varying in tuber weight from 14 ounces down to 1 ounce, and 
concluded from his results that the larger the seed tuber, the greater was 
the total yield, the earlier the bloom, the taller the plant, and the later the 
maturity. Plumb obtained a consistent decrease in net yield, however, as 
the size of the seed tuber increased. He failed to duplicate his test plots. 

Whole as compared with cut seed 
The advisability of cutting seed potatoes depends on three factors: 
the cost of labor, the cost of seed, ancl the relative merit of whole as com- 
pared with cut seed in the effect on yield. Literature reporting experi- 
mental data on this question considers only the last-named factor. Cutting 
seed tubers at once facilitates loss of sap by bleeding, and the entrance of 



A Study of Factors Influencing the Yield of Potatoes 1217 

rot-producino- bacteria and fungi. Appleman (1918) has shown that the 
transverse cutting of seed tubers permits development in the median and 
basal eyes which would remain more or less dormant if the tubers were 
planted whole, due to the exclusive development of the terminal eyes. 
This would indicate a more economical use of seed than is the case if 
whole tubers are planted. Aicher (1917) and Welch (1917), in a three- 
years duplicate experiment on irrigated land in Idaho, compared whole and 
cut seed as to stand, earliness, and yield. Aicher obtained an earlier 
growth, a more prolific top growth, a larger total yield, and a smaller 
marketable yield, from whole than from cut tubers. Welch obtained a 
better stand from the whole tubers, but one that was not commensurate 
with the extra amount of seed recjuired. • He also obtained a smaller 
marketable yield from whole than from cut tubers, but he does not agree 
with Aicher that wholeness has anything to do with earliness. The 
writer is of the conviction that, so far as the relative merit of whole and of 
cut seed is concerned, these tests of Aicher and Welch are no true criterion. 
The much greater rate of planting of whole seed over cut seed invalidates 
any conclusion that may be drawn relative to differences in yield. Har- 
wood and Holden (1893) reported an interesting experiment attempted 
by the Tennessee station to test the comparative yields from whole tubers 
and from an equal weight of halved tubers from the same lot of seed. 
This eliminated any possible difference in rate of planting, so far as total 
weight of seed was concerned, but the fact that the half tubers were 
planted on twice as much area as the whole tubers vitiated the object of 
the experiment. Nearly two and a half times as much merchantable 
yield was obtained from the half tubers as from the whole. These same 
authors report a more nearly accurate test made by the New York station, 
in which equal-weight seed pieces of whole and cut types were used. The 
average total yield per acre was the same from the whole and the cut seed, 
but the marketable yield per acre from the cut seed was nearly double that 
from the whole seed. 

Large as compared with small seed pieces 
The question of size of the seed piece in relation to yield has been treated 
experimentally on the basis of both weight and proportion of tuber. 
Neither basis can be considered quite separately, and both naturally 
involve the question of rate of planting, the spacing of the seed remaining 
constant. The hundreds of experiments recorded for the study of size 
of seed piece are virtually tests of the most efficient rate of planting, tho 
the objects of and the conclusions for them have been related to size of 
piece alone. 

Plumb (1890), comparing the yields from whole tubers, halves" quarters, 
and single-eye pieces, obtained an increased yield with every increase in size 
of seed, tho the greatest merchantable yield was obtained with the half 



1218 Earle V. Hardenburg 

tuber. As early as 1886, Samuel Johnson (1886) compared the yields 
from whole and half tubers and from three-, two-, and one-eye pieces, and 
found that, whereas the whole tuber gave the highest total yield, the 
three-eye piece gave the highest marketable yield. Two years later, 
comparing the same types of seed, Johnson (1888) obtained a consistent 
gain in yield with each increase in size of seed, and a decrease in percentage 
of stand with each decrease in size of seed. Johnson did not report 
whether his highest total yields were also the highest net yields. 

Taft (1892), in a three-years test, compared the efficiency of various 
rates of planting, by planting whole, half, quarter, and eighth tubers, 
and single-eye pieces, equidistant in the row. His net yields increased 
up to and including the half tuber, altho the highest total yield came froirJ 
whole seed. Adams (1889), using whole, half, two-eye, and one-eye seed 
pieces, obtained an increased total yield up to and including whole seed, 
with the greatest marketable yield from two-eye pieces. He did not report 
in terms of net yield. Green (1887) reported a two-years average test of 
the yields from one-eye, two-eye, half, and whole seed pieces as increasing 
with the size of piece used, but made no mention of the net or the market- 
able yields or of the rate of planting. Hutcheson and Wolfe (1917) made a 
three-years comparison of the yields from single-eye, half-ounce, one- 
ounce, and two-ounce pieces. Whereas both total and marketable yield 
increased up to and including the two-ounce piece, the increased yield 
from the two-ounce over that from the one-ounce piece was not sufficient 
to warrant the use of pieces larger than one ounce in weight. Aicher 
(1917) and Welch (1917), in their duplicate experiment covering three 
years, concurred in the results showing the highest total yield to be from 
whole seed and the highest marketable yield from quartered seed pieces, 
in a comparison of whole, halved, and quartered seed pieces. These 
investigators were agreed also that the number of stalks per hill increased 
with the size of piece planted, a fact which probably accounts for the smaller 
percentage of marketable tuljers from the largest seed. 

Appleman (1918) tested the influence of weight of seed piece on yield 
by varying the weight from 0.08 to 1.75 ounces in the variety McCormick 
and from 0.61 to 1.46 ounces in the variety Irish Cobbler. To give due 
consideration to rate of planting in such a test, he showed how this vari- 
ation in McCormick increased the amount of seed from 1.1 to 24.96 
bushels per acre. He obtained, in both varieties, an increased total yield 
with each increase in weight of the seed piece. 

Zavitz (1916) has furnished perhaps the best contribution to the study 
of this factor. In ten tests, covering five years, he compared one-sixteenth-, 
one-eighth-, one-quarter-, one-half-, one-, and two-ounce seed pieces, the 
rate of planting varying from 1.3 to 41.2 bushels per acre and the number of 
eyes in each set remaining constant. With no seed piece weighing more 
than two ounces, Zavitz found increased net, marketable, and total 



A Study of Factors Influencing the Yield of Potatoes 1219 

yields for each increase in size of seed pieces used. But here he also failed 
to consider the factor of rate of planting. In another five-years experi- 
ment, however, testing the efficiency of various spacings of seed, he has, 
apparently unconsciously, furnished some much-needed information. This 
test showed that with the same weight of seed planted per acre, the one- 
ounce sets, planted twice as close as the two-ounce sets, gave greater 
total, marketable, and net yields. 

Hume, Champlin, and Oakland (1914) compared large, medium, and 
small seed pieces, eye frequency being constant, and observed an average 
increase of total yield, in two varieties, of 70.9 per cent in large seed pieces 
and 55.5 per cent in medium seed pieces, over that from the small seed 
pieces. Emerson (1907) conducted a very comprehensive and accurate 
test of the relation of size of seed piece to yield under a constant rate of 
planting. Planting eighth, quarter, and half tubers, 6, 12, and 24 inches 
apart, respectively, he used 18 bushels of seed per acre in each plot. This 
gave him the highest total yield per acre from the quarter-tuber pieces 
and the lowest total yield from the half tubers. This, together with the 
test by Zavitz (1916) previously cited, would indicate that with the same 
rate of planting per acre, smaller pieces, down to one ounce, planted closer, 
are likely to give larger yields than larger pieces planted farther apart. 

Schweitzer (1896), with twelve varieties in a one-year test, compared 
the total yields and the yields of small tubers from one-eye, two-eye, 
quarter-tuber, half-tuber, and whole-tuber pieces. This gave a variation 
in rate of planting of from 4 to 87 bushels. His total yield increased with 
each increase in size of seed piece and in rate of planting. Also, the per- 
centage of small potatoes increased from 8.9 for one-eye pieces to 26.4 
for whole tubers as seed. 

Harwood and Holden (1893) brought together a compilation of experi- 
ments from thirteen stations designed to test the relation of size of seed 
and rate of planting, to yield. In summarizing the comparative value of 
whole and of half tubers as seed, they showed that the results of a sub- 
stantial majority of these experiments were in favor of the whole tuber, 
not only for total and marketable yield, but also for net marketable 
yield and net value of the crop. Similarly, a majority of the compari- 
sons of the half-tuber and the two-eye piece favored the former thruout. 
In drawing such conclusions, it must be borne in mind that these dif- 
ferences in yield were due to an increase in the amount of seed used 
because of the larger size of the seed piece. These authors called at- 
tention to the conclusions of the Ohio station, that "despite the fact 
that whole potatoes give more small potatoes than one and two eye cut- 
tings, it is also true that they give more large potatoes." 

The foregoing review of the question of large as compared with small 
seed shows that few tests have actually proved any superior merit of large 
seed, except as the amount used per acre was increased. The few tests of 



1220 Earle V. Hardenburg 

a more comprehensive nature have indicated that equivalent amounts of 
smaller seed pieces, down to a minimum weight of one ounce, planted 
closer, may give even more efficient results. With an expensive and 
limited seed supply, the latter type of seed and system of planting would 
seem advisable. 

Number of eyes 

Many of the older potato growers attach considerable importance to 
the number of eyes to be left, in cutting seed potatoes. While a few 
growers cut single-eye pieces, the majority prefer pieces containing two eyes. 
Whether or not there is any significance in the relation of this factor to 
yield or to quality of the crop, it is automatically controlled, in practice, 
by the size of the seed piece, the importance of which has already been 
discussed. Arthur (1892) showed, in very definite terms, that the yield of 
large tubers decreases with the use of seed tubers weighing more than 
four and one-half ounces. His results are in accord with those of many 
other experiments which show that increasing the number of eyes on the 
seed piece tends to reduce the average size of the resulting tubers. 

Whipple (1915) studied the influence of thinning to one stalk per hill, 
in a two-years test of nine varieties planted from two-ounce pieces irre- 
spective of the number of eyes. Thinning to one sprout improved the 
market shape and the uniformity of the crop, but Whipple's results do 
not justify any conclusion that either total or marketable yield was 
increased by thinning. The cost of thinning was therefore not warranted. 

Ballou (1910) has shown that varieties differ in the number of stalks per 
hill which will develop from a given size of seed piece. Bovee, having 
frequent eyes, developed more stalks per hill per unit of seed piece than 
did Carman No. 3, a variety of few eyes. Ballou obtained an increase 
in the unmarketable yield from every increase in size of seed piece or 
nmnber of eyes in both varieties. The most profitable net yield in the 
Bovee was obtained from two-eye pieces planted at the rate of 15 bushels 
per acre, and in the Carman No. 3 from half-tuber pieces planted at the 
rate of 25 bushels per acre. 

Again it remained for Zavitz (1916) to contribute the real test of the 
influence of eye frequency on yield, by eliminating the factor of size of 
seed piece. Using one-ounce seed pieces thruout a five-years test, he 
compared the results from seed pieces containing one, two, three, four, 
and five eyes, respectively, and found that as the number of eyes increased, 
the average total yield increased and the percentage of marketable yield 
decreased. The difference in marketable yield, however, was in no case 
more than 5 per cent. It is therefore evident from Zavitz 's work that 
the yield is proportional to the number of stalks per hill, as well as to the 
size of the seed piece, and that nothing is to be gained by cutting to a 
certain minimum number in preparing seed for planting. 



A Study of Factors Influencing the Yield of Potatoes 1221 

Types of seed used in the four regions surveyed 

Obviously there are many difficulties in the way of attempting to deter- 
mine by survey methods the relation of type of seed to yield. Whether 
or not a grower decides to cut his seed rather than plant it whole, depends 
principally on the size of the tubers he has for seed, because, in cutting 
for seed, most growers have a definite size of seed piece in mind. Growers 
in Steuben County, more than in other regions, showed a tendency to 
plant seed of low market value. Much cull seed was therefore planted 
whole in 1912. Since practically all seed used on Long Island is bought 
and is of a grade higher than the average, growers there find it economical 
to cut nearly all of it. Good seed is more cheaply produced and more 
plentiful in Franklin and Clinton Counties, and therefore relatively large 
seed is used there, and more of it is planted whole than in the other regions. 
The proportion of whole and of cut seed used in the four surveyed regions 
is shown in table 54: 



TABLE 54. Pee Cent of Growers Using Whole and Cur Seed, in the Four Regions 

Surveyed 



Type of seed 


Long 

Island, 

1912 


Steuben 

County, 

1912 


Monroe 

County, 

1913 


Franklin 

and 
Clinton . 
Counties, 

1913 


Whole 

Whole and cut 






100 


1 
40 
59 



26 
74 


10 
39 


Cut 


51 



Evidently there are very few growers who feel that their seed is small 
enough, cheap enough, or low enough in quality to warrant planting it 
whole. However, it is not possible to jvidge from table 54, by the amount 
of each type of seed used, which region used the best seed in the year for 
which the data were taken. It has not been possible to study the influence 
of the size of seed piece on yield, in these regions, because of the impossi- 
bility of determining even the average size of the seed used. In studying 
the influence of the size or the degree of wholeness of the tubers used for 
seed, definite conclusions cannot be drawn because of the lack of uniformity 
in the opinions of the growers as to the meaning of the terms large, medium, 
and small, and furthermore because in many cases more than one type of 
seed was used. The data are presented here for whatever significance they 
may have. 

On Long Island, as already stated, all the seed used in 1912 was cut. 
A comparison of the yields from large tubers cut and from medium-sized 
tubers cut, is given in table 55. The difference of 8.6 bushels per acre in 



1222 



Earle V. Hardenburg 



TABLE 55. Relation of Type of Seed to Yield on 171 Long Island Farms in 1912 



Type of seed . 


Number 

of 

farms 


Average 
yield 

per 

acre 
(bushels) 


Average 

amount 

of seed 

used 

(bushels) 


Average 

value 
of manure 

and 
fertilizer 


Large cut 


99 

72 


163.1 
171.7 


12.0 
13.0 


$31 24 




33.18 






Total 


171 
















Average 




167.0 


12.4 


$31 48 









favor of the medium-sized tubers cut is no more, and is probably less, 
than should be expected from the increased amount of seed and fertilizer 
used by this group of growers. Apparently there was little choice between 
the two sizes of tubers used. 

The practice of cutting seed of egg size for planting was probably com- 
moner in Steuben County than in the other regions. Some whole seed 
which might be classed as cull was also used by some of the less progressive 
growers, as shown in table 56. The yields given in table 56 correlate 

TABLE 56. Relation of Type of Seed to Yield on 217. Steuben County 

Farms in 1912 



Type of seed 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Average 

amount 

of seed 

used 

(bushels) 


Average 
value of 
manure 

and 
fertilizer 




98 

11 

102 

4 

2 


149.7 
139.1 
135.7 
95.5 
181.1 


9.9 
10.1 
10.3 

9.4 
11.5 


$10.94 


Large cut 

Medium-sized cut . . 


12.70 
10.83 


Small whole . . 


6.84 


Medium-sized whole 


9.53 






Total 


217 




















146.5 


10.4 


$10.89 









rather closely with the rate of planting and the value of manure and ferti- 
lizer used. The four growers who used small whole seed also used the 
least seed and fertilizer, and, as a result, harvested the lowest average 
yield. In view of the amount of seed and fertilizer used, the growers 



A Study of Factors Influencing the Yield of Potatoes 1223 

who used a combination of both large and medium-sized cut seed obtained 
a more profitable net yield than did those who used either large or medium- 
sized cut seed alone. 

So far as is possible from the data taken, the relation of type of seed to 
yield in Monroe County is shown in table 57. More than a third of the 



TABLE 57. Relation of Type of Seed to Yield 

Farms in 1913 



257 Monroe County 



Type of seed 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Average 

amount 

of seed 

used 

(bushels) 


Average 
value of 
manure 

and 
fertilizer 


Medium-sized cut 


120 

18 
30 
52 
17 
2 

18 


143.5 

132.5 

132.1 

131.5 - 

129.5 

122.9 

120.5 


12.0 
12.8 
12.8 
13.1 
12 3 
11.0 

11.4 


$11 75 


Medium-sized whole and large cut 

Small whole and medium-sized cut 


13.26 
9.56 
12.56 




12.66 




12.28 


Medium-sized whole and medium-sized 
cut 


9.11 






Total 


257 




















136.2 


12.3 


$11.63 









growers in this region used medium-sized cut seed in 1913. Judging from 
the average amount of seed and fertilizer used by these same growers, 
they obtained a more profitable net yield than did the growers who used 
either large cut seed or large and medium-sized cut seed. The real expla- 
nation as to why the group using medium-sized whole and medium-sized 
cut seed obtained the lowest average yield, lies in the fact that these growers 
used considerably less than the average amount of seed and fertilizer. 

Except that more whole seed was used in Franklin and Clinton Counties, 
the types of seed used there correspond fairly closely to those reported for 
Monroe County. The fact that about a third of the growers in this 
region claimed to have used large cut seed indicates that these growers 
use seed of larger average size than is used in any of the other regions. 
The relation of type of seed to yield here is shown in table 58. The com- 
parative yields from large cut and medium-sized cut seed agree very well 
with the majority of the experiments previously cited, which showed 
greater yields from the larger seed, due to the greater amount of seed 
planted. The difference of about 8 bushels per acre of average yield 
between medium-sized cut and medium-sized whole seed, however, does 



1224 



Earle V. Hardenburg 



TABLE 58. 



Relation of Type of Seed to Yield on 292 Franklin and Clinton County 
Farms in 1913 



Type of seed 


Num- 
ber of 
farms 


Average 

yield 
per acre 

(bushels) 


Average 
amount 
of seed 

used 
(bushels) 


Average 
value of 
manure 

and 
fertilizer 


Large cut 

Medium-sized whole and large cut 

]\ledium-sized whole an ' medium-sized 
cut 


97 
G4 

21 
42 
32 
8 
6 
22 


189. 1 

182.7 

181.5 
174.6 
166.7 
166.1 
157.8 
157.3 


12.9 
12.4 

11.8 
11.1 
11.0 
12.0 
11.1 
9.9 


$13.61 
12 .to 

10 49 


Medium-sized cut ... 


12 91 


Medium-sized whole ... .... 


13 02 


Medium-sized and large cut 

Small whole and large cut 


14.08 
15 81 


Small whole and medium-;ized cut 


12.01 


Total 


292 




















. 178.5 


11.9 


$12.96 









not agree with the experiments previously cited for the factor of whole as 
compared with cut seed. The apparent discrepancy cannot be attributed 
to differences in amount of seed and in value of manure and fertilizer, as 
these factors average approximately the same for both groups. 

A rather striking effect of the rate of planting is shown in table' 58, 
where the types of seed are arranged according to the average yields 
obtained from each. In fact, thruout these studies of the relation of type 
of seed to yield, it has been shown that those types which required the 
highest rate of planting were productive of the highest average yields. 



RELATION OF AMOUNT OF SEED TO YIELD 

The very marked effect of rate of planting on yield has been shown in the 
previous discussions of the effect of manure and fertilizer and of size of 
seed piece. A majority of the very large number of tests which have been 
conducted to determine the optimum number of bushels per acre to plant, 
indicate that in this country too little seed is generally planted, under 
average conditions. In contrast to this, the large yields obtained by 
European growers, who commonly plant from 30 to 40 bushels of seed per 
acre, are often cited. It does not follow, however, that similar rates of 
planting in New York would he productive of such yields. Land, labor, 
and climatic conditions in northern Europe are such that high rates of 
planting are not only possible but also profitable. As shown by the major- 
ity of experiments testing this factor, the most profitable rate of planting 



A Study of Factors Influencing the Yield of Potatoes 1225 

has seldom been exceeded in this country. Rate of planting is increased 
either by closer planting or by increasing the size of the seed piece. 

Harwood and Holden (1893) compiled the results of thirteen experiments 
conducted at the Michigan station to determine the optimum rate of 
planting as well as the optimum size of seed piece. The rates of planting 
varied from 2.7 to 58.9 bushels per acre. The net yields showed that the 
optimum rates of planting varied from 10.8 to 48 bushels per acre. In 
only four tests was the best rate of planting higher than 24 bushels. 
Emerson (1907) tested rates of planting varying from 6 to 36 bushels per 
acre when eighth, quarter, and half tubers were used. He found that 12, 
18, and 36 bushels per acre were the best amounts to use for these respective 
sizes of seed pieces. Macoun (1905), by varying the spacing of the seed 
from 10 to 18 inches and thereby varying the rate of planting from 35 to 
19 bushels per acre, obtained the highest net yield from 25 bushels of seed. 
Kohler (1910), using the varieties Early Ohio and vSir Walter Raleigh, 
varied the rate of planting in each by 3 and by 2j bushels, respectively, 
from 6 to 21 bushels in the Early Ohio and from 5 to 20 bushels in the Sir 
Walter Raleigh. He obtained the highest marketable yield in the Early 
Ohio from 12 bushels of seed, and in the Sir Walter Raleigh from 17.5 
bushels. 

Zavitz (1916), using only one-eye pieces, varied the rate of planting 
from 1.3 to 41.2 bushels by increasing the size of the seed piece. Here 
both the highest net yield and the highest marketable yield were obtained 
from using 41.2 bushels of seed. Zavitz's test covered a five-years period, 
and is therefore more significant in this respect than the other tests just 
reported. 

The wide variation in the optimum rate of planting shown by the 
experiments here reported, indicates that the available soil moisture and 
the fertility have much influence in limiting the stand of plants which 
will develop to maximum productivity. In other words, the potato soils 
of Steuben County, which are naturally low in fertility, cannot be expected 
to produce the average yields that are obtained in Monroe, FrankUn, and 
Clinton Counties. From a review of the data available up to this time, 
it seems a safe assumption that, under at least average conditions, the rate 
of planting may be profitably increased from its present average to from 15 
to 18 bushels per acre. Where weed control is important, labor scarce 
and expensive, and land relatively cheap, checki'owing is a common 
system of planting. Tho this system naturally lowers both the rate of 
planting and the resulting yield, both may be increased by increasing the 
size of seed piece used. 

Rate of planting on Long Island 
In spite of the fact that the growers on Long Island pay relatively high 
prices for nearly all of their seed every year, they have apparently learned 



1226 



Earle V. Hardenburg 



that it is not profitable to plant less than the average of 12.5 bushels per 
acre. The influence of the rate of planting on the yield for this region 
in 1912 is shown in table 59. It may be seen in this table that there was 

TABLE 59. Relation o- Rate of Planting to Yield on 330 Long Island Farms in 

1912 



Rate of planting 
(bushels per acre) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Average 
amount 
of seed 
used 
per acre 
(bushels) 


Average 
value of 
manure 

and 
fertilizer 


Less than 11 


71 
68 
77 
49 
33 
32 


148.9 
181.4 
161.7 
179.5 
193.0 
202.0 


9.9 
11.3 
12.2 
13.4 
14.1 
15.6 


$28.79 


11-12 


32 34 


12-13 .- 


31 50 


13-14 


33 52 


14-15 


33 06 


15 and more 


36.63 


Total 330 
















Average 




175.5 


12.5 


$32.40 



Yield per acre, in bushels 



ci . a. 



CO ^ 



03 9 

^ 11 

S 12 

^ 13 

o 14 

•I 15 

-S 16 

m 17 

18 









1 


















1 


1 


1 


1 




1 












4 


3 


1 


1 


1 






1 






2 


8 


8 


15 


9 


7 


2 


1 


2 






2 


3 


8 


20 


7 


11 


6 


6 


3 




1 


- 2 


6 


12 


23 


10 


11 


4 


4 


1 




1 




2 


5 


12 


5 


11 


6 


4 


2 




1 


1 


1 




4 


3 


13 


3 


6 


2 








2 


1 


2 

1 
1 


3 
3 

1 


5 
1 


4 
1 


1 

1 


2 







27 



81 



23 



13 



330 



43 60 27 

r = 0.273 ± 0.034 

Fig. 140. correlation of rate of planting and yield on 330 long island farms 

in 1912 



A Study of Factors Influencing the Yield of Potatoes 1227 

a tendency among the growers who planted the most seed to use also 
somewhat more than the average value of manure and fertilizer. Also, 
there was more spraying for blight among these growers. However, the 
same marked influence on the yield from the rate of planting is shown in 
table 24, under the discussion of manure and fertihzer, where each of these 
factors is treated under the various subheads. The single discrepancy in 
table 59, in the group of growers using from 11 to 12 bushels of seed, is 
due, at least in part, to the larger value of manure and fertilizer used by 
this group. Since the average number of eyes per piece gradually in- 
creased from the lowest to the highest rate of planting, it may be con- 
cluded that the rate of planting varied not so much according to closeness 
of planting as according to size of seed pieces used. From table 59, it 
is apparent that the growers in this region who used as high as 15 bushels 
of seed per acre in 1912, did not use more than was profitable. Applying 
the biometrical measure of correlation of this factor with'yield (fig. 140) 
shows the significant coefficient 0.275 ± 0.034. 

Rate of 'planting in Steuben County 
In the four regions surveyed, Steuben County growers used the least 
seed, planting an average of 'only 10.1 bushels per acre in 1912 (table 60). 
The highest rate reported by any of the 360 growers was 18 bushels, and 

TABLE 60. Relation of Rate of Planting to Yield on 360 Steuben County Farms 

IN 1912 



Rate of planting 
(bushels per acre) 


Num- 
ber of 
farms 


Average 

yield 
per acre 

(bushels) 


Average 
amount 
of seed 
used 
per acre 
(bushels) 


Average 
value of 
manure 

and 
fertilizer 


6-8 


19 

138 

126 

57 

20 


117.8 
123.1 
138,3 
147.7 
191.3 


6.9 
8.6 
10.2 
12.5 
15.4 


$ 9.17 


8-10 


9.27 


10-12 


10.17 


12-14 


10.96 


14-18 


12.63 






Total 


360 




















136. ! 


10.1 


$10.06 









there was a profitable increase in yield from every increase of 2 43ushels 
per acre planted, up to 18 bushels. Steuben County growers did not 
exceed the optiimmi rate of planting in 1912, and it is safe to recommerid a 
considerable increase in the average amount of seed used in that region. 



1228 



Earle V. Hardenburg 



Altho the increased jdelds were due partly to the increased values of 
manure and fertilizer used, this factor has been studied in a separate 
grouping in table 25 under the discussion of the value of manure and 
fertilizer for the region. The low average rate of planting for this county 
in 1912 was due partly to the planting of a considerable area in check- 
rows and partly to the use of small and relatively inferior seed. The data 
show that the amount of seed used probably did' not exceed the maximum 
which the relatively low soil fertility could support. The coefficient of 
correlation between rate of planting and yield for this region, 0.374 ± 
0.031 (fig. 141), is the highest found for any of the four regions. 

Yield per acre, in busliels 

lO O O O iQ O lO O-i-O OiOOiOOkO 

IM lO t^ O OJ "O t- O <M lO l^ O (M lO t^ 

T-H ■^ —I —I (M <M (MtMCOfOCOeO 

^ J. ^ 





?5 


IQ 


P- 


o 


s 


lO 


t^ 


o 


c^ 


lO 


t^ 


^ 


C^ 


»o 


















C-l 


c^ 


<M 


<M 


CO 


CO 












1 
























2 


2 


2 


1 


1 


















1 




2 


7 


4 


2 


4 




















2 


11 


15 


23 


15 


8 


5 


1 


2 














1 


3 


11 


13 


11 


7 


2 


















2 


5 


18 


20 


25 


15 


15 


4 


1 












1 






2 


2 


6 


2 


4 


1 


















3 


5 

1 
3 


8 
1 


7 
7 
1 
2 


8 
4 
2 

1 


5 
1 
1 
1 

1 


1 

1 
1 


2 

1 

2 

1 
1 




1 
1 






1 



20 

82 

51 

105 

18 

40 

13 

7 

10 

2 

1 

2 



1 360 



2 5 26 64 73 78 52 38 9 10 

, r -= 0.374 ± 0.031 

Fig. 141. correlation of rate of planting and yield on 360 steuben county farms 

IN 1912 



Rate of planting in Monroe County 

The average amount of seed per acre used in Monroe County in 1913 
was 12.5 bushels, which was the same average as was used on Long Island 
in 1912. The relation of this factor to yield is shown in table 61. Altho 
there was a tendency among the growers who planted the most seed to 
use more manure and fertilizer, the influence of seed is nearly as marked 
in this region as in the others. A few growers used as much as 20 bushels 
or more per acre, and, without using more fertilizer than was used bj^ 
growers planting from 14 to 16 bushels per acre, they obtained an average 
increase in yield of about 25 bushels per acre. It appears, however, that 



A Study of Factors Influencing the Yield of Potatoes 1229 



TABLE 61. 



Relation of Rate of Planting to Yield on-300 Monroe County Farms 
IN 1913 



Rate of planting 
(bushels per acre) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Average 
amount 
of seed 

used 
per acre 
(bushels) 


Average 
value of 
manure 

and 
fertilizer 


Less than 10 


38 
62 
111 
69 
20 


108. 2 
119.6 
120.1 
137.5 
163.2 


8.2 
10.3 
12.4 
14.5 
18.3 


$ 9.09 


10-12 


10.54 


12-14. . 


11.29 


14-16 . 


12.73 


16 and more ... .... 


12.14 






Total 


300 




















126.2 


12.5 


$11.28 









even the growers who planted the most seed did not exceed the optimum 
rate. A coefficient of correlation of 0.247 ± 0.037 between rate of plant- 
ing and yield for this region in 1913 is shown in figure 142. 

Yield per acre, in bushels 



J. ^ ^ ^ 

(M >0 l^ 



^ ^ i. 

O iM lO 



1 ci 



g 10 

« 11 

l!^ 

" 15 

° 16 

■I 17 

-S 18 

n 19 

20 
21 
22 
23 



Fig. 142 









1 
























I 


1 




1 


2 


1 














1 


4 


7 


2 


5 


1 
















1 


1 


6 


1 


1 




1 












1 


1 


8 
4 


8 
5 


9 
3 


11 
2 


2 




6 

1 


1 












2 


10 


22 


15 


9 


9 


5 


3 




1 




1 




1 


2 


4 


8 


12 


3 


1 


1 


1 












4 


7 


6 


5 


4 


3 


1 


1 










1 


3 

1 


6 
3 


4 

1 
1 


9 
3 

1 

1 
1 


8 

2 

1 


4 

1 

1 


1 
1 


1 
1 


V 


1 





7 38 70 50 61 34 24 

r = 0.247 ± 0.037 



1 1 



1 300 



correlation of rate op PLANTING AND YIELD ON 300 MONROE COUNTY FARMS 

IN 1913 



1230 



Earle V. Hardenburg 



Rate of planting in Fr-anklin and Clinton Counties 

The growers in Franklin and Clinton counties who were interviewed 
concerning their 1913 crop planted an average of 12 bushels of seed per 
acre, the rate varying from less than 10 to more than 18 bushels. The 
relation of this factor to yield in 1913 is shown in table 62. A study of 



TABLE 62. 



Relation of Ra.te of Planting to Yield on 300 Franklin and Clinton 
County Fabms in 1913 



Rate of planting 
(bushels per acre) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Average 
amount 
of seed 
used 
per acre 
(bushels) 


Average 
value of 
manure 

and 
fertihzer 


Less than 10 


38 


151.7 
167.0 

188.1 
185.6 
226.1 


8.5 
10.4 
12.3 
14.6 
17.9 


$12 72 


10-12 


88 
105 
52 


13.20 


12-14 


12.48 


14-16 


14.06 


16 and more 


17 


12.45 


Total 300 
















Average 


179.3 


12.0 


$13.01 



Yield per acre, in bushels 

O iQ O i^ C 

s ^ g 



J^ ci ^ 



Fig. 143. 



6 






1 














1 


7 




2 




1 


1 










4 


8 


2 


2 


3 


1 


3 




1 






12 


9 


2 


3 


7 


1 


7 






1 




21 


10 


5 


8 


13 


14 


9 


11 


2 


1 




63 


11 


2 


3 


4 


1 


9 


2 


2 


1 




24 


12 




6 


8 


18 


22 


11 


6 


5 


1 


77 


13 


1 




6 


2 


7 


4 


6 


1 




27 


14 




2 


4 


6 


6 


1 




3 


1 ' 


23 


15 




1 


3 


6 


8 


6 


4 


2 


1 


31 


16 






1 


1 


3 




1 






6 


17 












2 








2 


18 










1 


1 


3 






5 


19 























20 








1 






1 




2 


4 


























12 


27 


50 


52 


76 


38 


26 


14 


5 


300 








r 


= 0.367 ±0.034 











correlation of rate of planting and yield on 300 FRANKLIN AND CLINTON 
COUNTY FARMS IN 1913 



A Study of Factors Influencing the Yield of Potatoes 1231 

this table shows that there was less tendency in this region than in the 
others for growers using the most seed to use also the most manure and 
fertilizer. The figures are therefore all the more conclusive in showing 
the marked influence of rate of planting on yield. More seed than the 
amount indicated by the highest rate of planting here reported might 
have been used with profit in raising the 1913 crop. The coefficient of 
correlation, 0.367 ± 0.034 (fig. 143), is altogether significant and is the 
second largest value found for any of the four regions surveyed. 

date of planting 

The average date of planting potatoes in any region is determined pri- 
marily by the average date of the last killing frost in the spring, altho 
elevation, soil type, and the type of potato grown, are also important 
questions varying with different localities. Thus it is possible to plant 
earlier on light soils and at lower elevations, than on heavy soils and at 
higher elevations. However, because of the higher prices which usually 
obtain early in the harvest season, the earliest possible planting and 
harvest of early varieties is desirable. 

Zavitz (1916) reported results from thirty-six tests which consisted of 
planting two early, two medium, and two late varieties on four dates, 
two weeks apart, extending from May 31 to July 12. He carried this 
experiment thru a period of six years. Without exception, in all six 
varieties, both marketable and total yield increased directly with the 
earliness of planting. A continuation of this test the following year, 
with the plantings made on six dates instead of on four, gave the same 
general results. These tests were conducted on ordinary clay loam soil 
■at the Guelph station. Champlin and Winright (1917) compared for two 
years the yields from planting at intervals of fifteen days from April 1 
to July 1. For early digging the April 1 planting, and for late digging 
the May 15 planting, gave the best average yield for the two years. Such 
results as these are of value, even locally, only when the tests cover a 
period of several years. 

Because of the small variation in date of planting within each region 
surveyed for the one year, and because of the fact that conclusions on the 
best time to plant cannot be drawn from the yield of only one season, no 
attempt has been made to correlate the date of planting and the yield. 
The average date of planting in 1912 and in 1913, and the average date of 
the last killing frost in the spring, for the four regions, are shown in table 
63. The dates shown in this table indicate that Long Island is the only 
region in which the crop is planted before the average date of the last 
killing spring frost. It is evident that the Long Island growers ar^e willing 
to risk possible damage to the crop from frost in order to enhance the 
earliness of harvest. The planting season of this region is shown to be 
at least six weeks earlier than that of the others. 



1232 



Earle V. Hardenburg 



TABLE 63. 



Average Date of Planting, and Average Date of Last Killing Frost 
IN Spring, for the Four Regions Surveyed 



Region 



Average date 
of planting 



Average date of 
last killing frost 
in spring 



Long Island, 1912 

Steuben County, 1912 

Monroe County, 1913 

Franklin and Clinton Counties, 1913 



April 9 
May 20 
May 24 
May 30 



April 25 
May 10 
May 1 
May 10 



HAND AS COMPARED WITH MACHINE PLANTING 

The extent to which the potato crop of any region is planted by machine 
planters is determined principally by the average acreage, the system of 
spacing hills in the row, and the amount of large stones present in the 
fields. The writer (Hardenburg, 1915 a) found that in Steuben County, 
in 1912, when the average acreage of potatoes per farm was at least 5, 
the saving in labor cost by machine planting more than overbalanced the 
interest, depreciation, and repair costs of planting by this method. In 
regions where checkrowing is practiced, machine planting is impossible 
because potato planters cannot be used to plant in checkrows. As is 
shown later, much of the acreage in Steuben County was planted in this 
way in 1912. Some growers in Franklin and Clinton Counties find it 
impracticable to use planters because there are so many large stones in 
their fields. Conditions on Long Island, however, are almost ideal for 
machine planting, and it is done there almost entirely. The extent to 
which the acreage in each region was planted by hand and by machine, 
in the two years concerned, is shown in table 64: 

TABLE 64. Method of Planting and Type of Machine Used in the Four Regions 

Surveyed 



Region 


Per cent of total acreage 
planted by 


Per cent of total machine- 
planted acreage planted 
by 




Machine 


Hand 


2-man 
planter 


1-man 
planter 


Long Island, 1912 


98 
25 
74 

82 


2 
75 
26 
18 


23 
GO 

87 
56 


77 


Steuben County, 1912 


40 


Monroe County, 1913 


13 


Franklin and Clinton Counties, 1913 


44 




70 


30 


56 


44 







A Study of Factors Influencing the Yield of Potatoes 1233 

It might be presumed that growers of the larger acreages in each region 
would be more inclined to use planters than those having a smaller acreage. 
Whether this was true in these four regions is shown in table 65 : 

TABLE 65. Relation of Size of Potato Acreage to Method of Planting 



Region 


Average potato 

acreage per 

farm 


Average potato 

acreage planted 

by machine 


Average potato 

acreage planted 

by hand 


Long Island, 1912 - 

Steuben County, 1912 

Monroe County, 1913 . 


24.8 
14.6 
12.4 

7.2 


24.6 
17.9 
13.1 
6.5 


33.5 
13.7 
10.6 


Franklin and Clinton Counties, 1913 


8.6 



It is evident that growers in none of these region's find it unprofitable to 
plant by machine so far as average acreage of the crop is concerned. In 
Steuben and Monroe Counties there was a tendency to use more planters 
on the larger acreages. The 2 per cent of acreage on Long Island planted 
by hand averaged higher per farm than the balance which was machine- 
planted. The same relation held with the 18 per cent of hand-planted 
acreage in Franklin and Clinton Counties. It is clear, from tables 64 
and 65, that the average potato acreage per farm, considered in the light 
of percentage of total acreage planted by hand and by machine in each 
region, has no bearing on the extent of machine planting in these four 
regions. 

As indicated in table 64, two types of planters were commonly used. 
One was of the picker type, employing only one man, while the other 
was usually of the platform type and required two men for its opera- 
tion. As the second man on a two-man planter is charged with the duty of 
seeing that there are no skips, better stands of potatoes are expected from 
this type of planter. It is shown in table 64 that, whereas about three- 
fourths of the Long Island acreage was planted with one-man planters, 
the two-man type predominated in the other three regions. 

A study of the relative yields obtained from the acreage planted with each 
type in the four regions is shown in table 66. Of the total of 635 growers 
using machine planters — about one-half of all the farmers visited — the 
numbers using each type of planter were approximately equal. . The 
weighted averages in table 66 sliow that with about the same amount of 
seed per acre used in each planter, the yield was 19.3 bushels per acre 
higher from the acreage planted with the one-man planter. This average 
is not a true criterion of the two types of planters, however, because a 
large proportion of the total machine-planted acreage was on Long Island, 



1234 Earle V. Hardenburg 

TABLE 66. Relation of Type op Planter to Yield in the Four Regions Surveyed 





Two-man planter 


One-man planter 


Region 


Number 
of farms 


Average 

yield 
per acre 
(bushels) 


Average 
amount of 
seed used 
per acre 
(bushels) 


Number 
of farms 


Average 

jaeld 
per acre 
(bushels) 


Average 
amount of 
seed used 

per acre 


Long Island, 1912 

Steuben County, 1912.. . 

Monroe County, 1913'. . . 

Franklin and Clinton 

Counties, 1913 


74 
43 

175 

22 


171.6 
158.1 
132.1 

196.4 


12.5 
11.8 
13.2 

14.7 


249 

28 
28 

16 


175.6 

148.8 
116.3 

181.8 


12.5 
12.9 
13.2 

14.4 


Total.. 


314 






321 










Weighted average 

Unweighted average 


'.'.'.'.'.'. 


151.4 
164.6 


12.8 
13.1 




170.7 
155.6 


12.6 
13.2 



where 77 per cent of the machine-planted area was planted with the one- 
man type of planter. On the contrary, the difference in average yield, 
even on Long Island, was only 4 bushels per acre in favor of the picker 
planter, a difference so small as to lie within expected probable error. In 
the other three regions, where approximately equal rates of planting 
were used, the average yields favored the two-man planter by ditt'erences 
ranging from 9.3 to 15.8 bushels per acre. The unweighted averages in 
the table furnish a true comparison of the efficiency of the two types of 
planters, and may be accepted as an indication of the increased yield from 
a more perfect stand resulting from the use of the extra man on the plat- 
form planter. 

CHECKROW AS COMPARED WITH DRILL PLANTING 

A decision as to whether to plant potatoes in checkrows or in drills 
involves such factors as the cost of labor, available soil fertility and mois- 
ture, land value, weed control, and the use of machine planters. Of these 
factors, weed control is probably the most influential. The statements of 
many growers in Steuben County concerning their reason for checkrow 
planting emphasized the facility of weed control by cross cultivation in 
times when hand labor is scarce or when the pressure of other farm work or 
a wet season might make weed control otherwise difficult. The cost of 
labor as a determining factor is debatable, for, while checkrowing may 
reduce to a minimum the cost of taking care of the crop, the seed may be 
planted at less cost when planters are used, and planters cannot be used 



A Study of Factors Influencing the Yield of Potatoes 1235 

to plant the hills in checkrows. Moreover, while a marker is carried by 
the machine planter, extra labor is necessary to mark the field in checks 
for checkrow planting. As is shown in later tables, less seed per acre is 
usually planted by the checkrow system than by the drill method, since 
the seed pieces are spaced farther apart. Therefore, from the standpoint 
of land economy, checkrowing is the less desirable method where land is 
high in value, as on Long Island. An ample spacing between hills is shown 
by the typical checkrowed field in Steuben County illustrated in figure 144. 




Fig. 144. a checkkowed potato field, common in steuben county 



The smaller amount of seed planted per unit of space in the checkrow 
system may be desirable wherever soil moisture and fertility are likely to 
be taxed to their limit. However, the foregoing studies on the relation 
between rate of planting and yield do not indicate that this point was 
reached in Steuben County in 1912. 

Harwood (1893) reported comparative yields from twenty-four experi- 
ments conducted at the Michigan station, in which the varieties Early 
Ohio -and Rural New Yorker No. 2 were planted in hills and in drills. 
These tests are especially valuable because equal amounts of seed per acre 
were used in both systems of planting. Altho drill planting did not 
always give the higher yield, the general average showed a difference of 
12 bushels per acre for the Early Ohio and 29 bushels for Rural New 



1236 



Earle V. Hardenburg 



Yorker No. 2 in favor of this method. These differences were due, 
not to a difference in rate of planting, but to the system of spacing 
the seed pieces. Shepperd and Churchill (1911), using the variety Early 
Ohio and varying the rate of planting according to the space between 
seed pieces, compared the yields from planting at distances of from 10 to 
36 inches in the row. Here the yield decreased directly as the interspace 
increased, the 10-inch spacing giving the best yield. Zavitz (1916), in a 
six-years test, using equal-sized large whole seed and equal-sized medium 
whole seed, compared the results of spacing the seed 1, 2, and 3 feet. 
While his total yields increased directly as the spacing decreased, he 
obtained the largest net yield from the 2-foot spacing of large whole seed 
and from the 1-foot spacing of medium whole seed. In another test, 
running for nine years and with the same rate of planting in l)oth systems 
of spacing, he compared the yields from planting in checks 33 inches 
apart and from planting in the drill row with the seed pieces 1 foot apart. 
The results showed a nine-years average difference of 39.8 bushels per 
acre in favor of the drill-planted seed. From a review of the tests here 
reported, it appears that, irrespective of rate of planting, the yield from 
planting in drills is generally better than that from planting in checkrows. 
None of the 330 Long Island growers who were questioned regarding 
their 1912 crop had planted in checkrows. The almost universal use of 
planters in this region precludes the possibility of planting by the check- 
row method. Furthermore, the greater land values encourage economy 
of space, and the better yields from closer planting have convinced the 
growers of this region that drill planting is the better method. The method 
of planting most common in each of the four surveyed regions is indicated 
in table 67: 



TABLE 



System of Planting in the Four Regions Surveyed 



Region 


Per cent of 

growers planting 

in drills 


Per cent of 

growers planting 

by checkrow 


Long Island, 1912 


100 
29 
74 
18 







Steuben County, 1912. 


71 


Monroe County, 1913. 


26 


Franklin and Clinton Counties, 


1913 


82 









In contrast to the conditions on Long Island, approximately three-fourths 
of the crop in Steuben and in Franklin and Clinton Counties was planted in 
checkrows. This may be accepted as evidence that relatively cheap land 
and scarcity of labor make this the better method for these regions. About 
three-fourths of the Monroe County crop was planted in drills in 1913. 



A Study of Factors Influencing the Yield of Potatoes 1237 



The influence of the planting system on yield and on the amount of seed 
used is strikingly shown, for these three regions, in table 68. As is indicated 
in this table, in all three regions the drill system of planting gave an average 

TABLE 68. Relation of Planting System to Yield in Three of the Regions Surveyed 





Planted in drills 


Planted by checkrow 


Region 


Num- 
ber 
of 
farms 


Average 
yield 
per 
acre 

(bushels) 


Average 
amount 
of seed 

used 

per 

acre 
(bushels) 


Average 

value 

of 

manure 

and 
fertilizer 


Num- 
ber 
of 
farms 


Average 

per 

acre 

(bushels) 


Average 
amount 
of seed 

used 

per 

acre 
(bushels) 


Average 
value 

of 
manure 

and 
fertilizer 


Steuben County, 1912. . . 

Monroe County. 1913, . . 

Franklin and Chnton 

Counties, 1913 


101 
221 

54 


153,0 

128.5 

188.4 


12.2 
13.2 

14.5 


$12,09 
11.91 

12.94 


251 

77 

243 


129.2 
120.6 

177.2' 


9.2 
10.2 

11.4 


$ 9.35 
9.68 

13.20 


Total 


376 








571. 














Average 




156.6 


13.3 


$12.31 




142.3 


10.3 


$10 74 









yield varying from 7.9 to 23.8 bushels per acre higher than that from plant- 
ing in checkrows. It is shown further that invariably about 3 bushels 
more of seed per acre was required to plant by the drill system. The 
yield was sufficiently higher from this method, however, to more than 
pay for the extra seed necessary. 

On the basis of yield alone, these results favor the drill system of planting 
for all the regions surveyed. However, it is possible that there are seasons 
in which weed control is largely dependent on the possibility of cross 
cultivation. The choice at such times becomes one of producing a medium 
yield by checkrow planting with a minimum of labor, or a much smaller 
yield by drill planting. 

depth of PLANTING 

Depth of planting is a factor which, tho given some experimental atten- 
tion by various stations for many years, has received little consideration 
from the potato grower. The depth at which the seed piece is usually 
placed depends principally on the soil type and the method .of planting. 
Just as plowing and tillage are normally more shallow in heavy than in 
light soil, so potatoes are normally planted less deeply in heavy than in light 
soil. However, the depth at which the potato root system is allowed to 
develop depends not alone on the depth of planting, but also on the system 
of tillage employed. This is a factor too often neglected in the ^tudy of 
the influence of depth of planting on yield. For example, the seed may 
be planted shallow and the crop given ridge culture, or the seed may be 
planted deeper and the crop receive level culture. With either method 



1238 Earle V. Hardenburg 

the root system might develop at exactly the same depth. Therefore, in 
studying this factor by reviewing experimental data, false conclusions 
may easily be drawn. In studying it by survey methods, however, the 
problem is not so complicated, because of the fact that approximately 
the same system of culture is used thruout a given locality. 

Harwood (1893) reported a test of depth of planting conducted at the 
Michigan station, using three varieties and planting on sandy loam soil. 
The depth of planting was varied from 2 to 6 inches. The highest total 
yield came from the 3-inch planting, while the 4-inch depth was second best. 
The highest marketable yield came from planting 5 inches deep, altho there 
was practically no difference between this and the 4- and 6-inch depths. 
Emerson (1907) compared the yields from plantings at from 1- to 6-inch 
depths, and obtained a constant increase in yield with each increase in 
depth up to and including 5 inches. The 6-inch depth gave the second 
highest yield. Emerson concluded that the better qualit}^ and shape of 
the tuber resulting from planting from 4 to 5 inches deep, more than offset 
the extra labor of digging necessary for these depths. Sandsten and 
Delwiche (1909) harvested the highest total yield from the 4-inch depth of 
planting, the yield decreasing with the increase in depth below that level. 
Shepperd and Churchill (1911) compared the yields from plantings at 
depths of 3, 4, 5, 6, 7, and 8 inches. The 4-inch depth gave 8 per cent 
higher yield than any deeper planting, and 4.5 per cent more than the 
3-inch depth. These investigators did not mention soil type, but reported 
the greatest yield of marketable tubers and the highest quality from the 
deeper plantings. 

Emerson (1914), studying the influence of depth of planting on the value 
of the harvested crop for seed purposes, planted at 1, 4, and 7 inches. 
Seed from the 7-inch planting yielded the best, both in total and in market- 
able yield, in both of the tests he conducted. Also, seed from the 4-inch 
planting yielded much better than did that from the 1-inch depth. Accord- 
ing to Emerson, the higher cfuality of the seed from such deep planting is 
probably due to the fact that it was produced under soil conditions which 
fluctuated very little in temperature and moisture. 

Clement and Werner (1917) did not mention soil type in reporting a 
six-years test on planting at depths of 3, 4, 5, 6, 8, and 10 inches. They 
obtained tha highest marketable yield from the 4-inch depth, and there was 
a fairly consistent decrease in yield from plantings above and below that 
depth. Macoun (1905) made a thoro test of the influence of depth of 
planting, by comparing the yields for six years, on sandy loam soil, from 
planting at depths of from 1 to 8 inches. In every one of the six years he 
obtained the best yield from the 1-inch depth of planting. The second- 
best average yield came from the 3-inch planting. Since Macoun explained 
that cultivation during each season eventually placed the seed at a depth 
of about 2^ inches, it cannot be correctly concluded that 1 inch was a 



A Study of Factors Influencing the Yield of Potatoes 1239 



better depth to plant than 3 inches. Macoun's yiekls decreased rapidly 
in the plantings that were deeper than 6 inches. Zavitz (1916), using the 
clay loam soil at the Ontario station for seven years, planted seed 1, 3, 5, 
and 7 inches deep, and practiced level cultivation. He obtained the best, 
and practically equivalent, yields from planting 3 and 5 inches deep. He 
noted that when his seed was planted either shallower or deeper than 4 
inches, the new tubers showed a tendency to develop nearer the 4-inch 
level than at the depth of planting. 

The evidence presented in the foregoing experiments indicates that, 
depending to some extent on the soil type and the kind of tillage, the yields 
are usually better when the seed is planted about 4 inches deep than when 
it is planted either shallower or deeper. The fact that tubers tend to 
form near the 4-inch level, irrespective of depth of planting, is in itself an 
indication that soil moisture and temperature are the most favorable at 
this depth. While seed planted deeper is normally subjected to tempera- 
tures too cool for rapid growth, and the resulting crop forms too deep to 
be dug easily, seed planted less deep is subjected to a greater fluctuation 
in moisture and temperature, resulting in ill-shaped tubers and very often 
in a high proportion of sunburned or even blighted tubers. 

In this investigation an attempt was made to determine whether soil 
type and method of planting have any influence on depth of planting. 
The average depth of planting in each region, by machine, by hand, and 
for the region, is shown in table 69: 

TABLE 69. Depth of Planting in the Foub Regions Surveyed 



Region 




Average 

depth 

planted 

by hand 

(mches) 



Long Island, 1912 

Steuben County, 1912 

Monroe County, 1913 

Franklin and Clinton Counties, 1913 



3.4 
3.1 
3.0 
2.5 



Of the four regions, the deepest planting is found on Long Island and 
the shallowest in Franklin and Clinton Counties. Inasmuch as the 
potato soils of these two regions are lighter than those of either Steuben or 
Monroe County, no influence of soil type on depth of planting is evident 
in this study. The only significant influence of method of planting on 
depth is in Franklin and Clinton Counties, where machine-planted potatoes 
were placed, on the average, 0.7 inch deeper than those planted by hand. 
Whether or not the average depth of planting shown for each region 



1240 



Earle V. Hardenburg 



approximates the optimum depth is considered in the following paragraphs 
and tables. 

The relation of this factor to yield on Long Island in 1912 is shown in 
table 70. The depth of planting appears to have influenced the yield in 

TABLE 70. Relation of Depth of Planting to Yield on 329 Long Island Farms in 1912 



Depth planted 
(inches) 


Number 
of farms 


Average 

yield 
per acre 

(bushels) 


Average 
amount of 
seed used 
per acre 
(bushels) 


Average 

value of 

manure and 

fertilizer 


Less than 3 


68 

144 

99 

18 


166.7 
178.0 
176.7 
182.2 


12.1 
12.5 
12.9 

12.8 


$30.25 


3-4 


32.60 


4-5 


33.41 


5 and more 


33.65 






Total .... 


329 




















175.6 


12.5 


$32.42 









this region very little. Altho the average yield increased slightly as the 
depth increased, the increase in yield beyond the 3-inch depth was no 
greater than would probably be due to the slight increase in seed and in 
the value of manure and fertilizer used. Apparently, the average depth of 
3.3 inches for 1912 was approximately the best. 

The results of a similar study in Steuben County are shown in table 71 : 



TABLE 71. 



Relation of Depth of Planting to Yield on 360 Steuben County Farms 
IN 1912 



Depth planted 
(inches) 


Number 
of farms 


Average 

yield 
per acre 
(bushels) 


Avera-e 
amount of 
seed used 
per acre 
(bushels) 


A erage 

value of 

manure and 

fertlHzer 


Per cent 
of total 

yield 

rotted in 

field 


1-2 


6 
83 
179 
92 


148,1 
139.6 
134.4 
136.0 


10.1 
10.2 
10.1 
10.1 


$ 9.39 
11.09 
9.79 
9.97 


1 .0 


2-3 


14.5 


3-4 


14.7 


4 and more 


17.4 


Total. 


360 


















• 


Average, 3.1 inches.. 




136.4 


10.1 


$10.06 


15.2 



A Study of Factors Influencing the Yield of Potatoes 1241 

Altho six growers are too few to permit of the drawing of definite conclusions 
as to the shallowest planting found, there is considerable evidence that 
planting not more than 2 inches deep in the heavy soils of Steuben County- 
is desirable, at least in a year as wet as was 1912. Under a constant rate 
of planting at all depths, and with the least manure and fertilizer used at 
the shallowest depth of planting, this depth gave the highest average 
yield and the smallest percentage of field-rotted tubers in 1912. In fact, 
the percentage of field rot increased with the depth of planting. Assuming 
that there had been no rot from blight and we't weather that year, the 
average yield of the fields planted at the shallowest depth would still have 
been the highest. 

The relation of depth of planting to yi^ld in Monroe County in 1913 is 
shown in table 72. It is clear from this table that in 1913, planting shal- 

TABLE 72. Relation of Depth of Planting to Yield on 263 MonbBe County Farms 

IN 1913 



Depth planted 
(inches) 


Number 
of farms 


Average 

yield 
per acre 
(bushels) 


Average 
amount of 
seed used 
per acre 
(bushels) 


Average 

value of 

manure and 

fertilizer 


1-2 ... : 


11 
67 
110 
72 


151.5 
143.1 
131. '. 
132.6 


11.5 
12.8 
12.6 
12.5 


$10 43 


-3 


11 11 


3-4 

4 f.nd more 


11.83 
11.91 


Total . 


260 




















135.6 


12.6 


$11.61 









lower than the average of this region would have given more than average 
yields. With the least seed and fertilizer, the shallowest-planted fields 
gave the highest yields. Since the potato soils of this region are heavier 
than those of either Long Island or Franklin and Clinton Counties, and, 
in fact, are rather heavier than ideal potato soil should be, this gives further 
evidence that potatoes should be planted shallower on heavy than on light 
soils. With an increase in the value of manure and fertilizer, and an 
approximately constant amount of seed used per acre, an increase in depth 
of planting was accompanied by decreased yield on fields planted deeper 
than 2 inches. 

The importance of depth of planting as influencing yield in FranMin and 
Chnton Counties is shown in table 73. .The average yields in this region 
increased with the depth of planting, down to a depth of 4 inches. A part 
of this increase must be attributed to an increased use of seed and fertilizer. 



1242 



Earle V. Hardenburg 



TABLE 73. Relation op Depth of Planting to Yield on 300 Franklin and Clinton 
County Farms in 1913 



Depth planted 
(inches) 


Number 
of farms 


Average 

yield 
per acre 
(bushels) 


Average 
amount of 
seed used 

per acre 
(bushels) 


Average 

value of 

manure and 

fertilizer 


Less than 2 


44 
111 
91 
54 


172.3 
175.4 
184.9 
182.6 


11.2 
11,9 
12.3 
12.4 


$12 27 


2-3 


12 95 


3-4. . . 


13 25 


4 and more . 


13 25 






Total 


300 




















179.3 


12.0 


$13.01 









The evidence in table 73 indicates that the yields began to decrease from 
planting at depths greater than 4 inches. Evidently, in soils as light as 
those of this locality, planting at greater depths than the average of 2.6 
inches for 1913 may be recommended. 

Depth of planting is a factor which would require controlled experi- 
ments covering several years in order to determine the most effective 
depth for any given region. The evidence of a single year from the sur- 
veyed regions indicates that in the heavier soils it is safe to plant shallower, 
and in the lighter soils deeper, than the average depth for 1912 and 1913. 

DEPTH OF CULTIVATION 

The term cultivation has been used so promiscuously in agricultural 
literature that it seems well to define its limitations as used in this study 
before entering on any discussion of its influence on the yield of potatoes. 
Cultivation has for its primary objects, weed control and moisture con- 
servation. Any operation on the crop after it is up, which stirs the soil 
for either or both of these purposes, is therefore included within the meaning 
of the term as here used. Such operations as using the weeder, pulling 
weeds, hoeing, and hilling or ridging the crop, are comprehended by the 
term. This will account for the great frequency of cultivation noted 
in the studies of the influence of this factor on yield. 

Harwood (1893) reported the results of forty-four tests on the influence 
of depth of cultivation on yield. Considering 1.5 inches as shallow and 
5 inches as deep culture, forty of the forty-four tests gave total and 
marketable yields favoring deep culture. As a rule, the greatest yield of 
small and sunburned tubers was obtained from shallow culture. Schweit- 
zer (1896), in a one-year test on potatoes planted 4 inches deep, compared 
deep and shallow tillage. Altho his yields were almost equal, he obtained 



A Study of Factors Influencing the Yield of Potatoes 1243 

a slightly higher marketable yield from deep cultivation and a slightly 
higher total yield from shallow cultivation. 

Information on depth of cultivation in the four regions surveyed, was 
obtained m relative terms, denoting general depth rather than actual 
inches The variation m depth thruout the growing season was noted also. 
It has therefore not been possible to make any definite correlation of this 
factor with yield m these studies, because of the fact that much variation 
in opmion may have existed among growers as to just what constituted 
deep medium, or shallow culture. Furthermore, it is a common practice 
in all four regions to ridge the rows more or less late in the growing season 
Ihis practice really amounts to a deep cultivation at the center of the row 
while httle or none is given close to the plants. Altho considerable varia- 
tion m the depth of cultivation was found at different times during the 
growing season, a plurality of the growers practiced relatively deep early- 
season cultivation and shallow late-season cultivation. Tliis would seem 
to be good cultural practice, inasmuch as deep tillage early would enlarge 
the soil area suited to tuber and root development, while shallower tillage 
later would avoid undue root pruning and disturbance after tuber forma- 
lion. 

The practice with respect to this factor, and its apparent influence on 
yield m each of the regions, is shown in table 74. Of the 1290 growers 

TABLE 74. Relation of Seasonal Depth of Cultivation to Yield in the Four Regions 

Surveyed 





Long Island, 
1912 


Steuben Coimty, 
1912 


Monroe County, 
1913 


Franklin and 

Chnton Counties, 

1913 


Type of 
cultivation 


Num- 
ber 
of 

farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber 

of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber 
of 

farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber 
of 

farms 


Average 

yield 
per acre 
(bushels) 


Deep early and 

shallow late 

Medium early and 

medium late .... 
Deep early and 

deep late 

Deep early and 

medium late .... 


267 

9 

34 

12 


172,9 
165.1 
195.0 
149.3 


164 
112 
38 
23 


141.5 
123.3 
149.5 
121.6 


106 
21 
67 
29 


146.0 
130.3 
128.5 
122.9 


89 
58 
35 
30 


183.7 

172.1 

■ 175.4 

196.2 


Total 


322 




337 




223 




212 






^ 


Average 




175.2 




135.7 




136.7 




181.2 



1244 Earle V. Hardenburg 

concerned in the whole survey, approximately 1100 practiced one of the 
four types of cultivation listed in this table. Each of the remainder prac- 
ticed one of the other possible five types of deep, medium, and shallow 
early- and late-season cultivation. On the basis of weighted averages, the 
best average yields were obtained from deep cultivation early in the season 
and shallow cultivation late. 

RIDGE AS COMPARED WITH LEVEL CULTURE 

The system of potato culture in vogue almost universally thruout the 
New England and Middle Atlantic States has been that of varying degrees 
of ridging or hilling. An extreme ridging, comparable to that followed in 
Aroostook County, Maine, is practiced in Franklin and Clinton Counties. 
In only a few limited areas, notably the Long Island potato areas, is any- 
thing approaching level cultivation common in these sections of the 
United States. Regardless of the fact that several station experiments 
have shown superior merit in point of yield from level culture, ridge culture 
is by far the commoner. The more obvious advantages of ridge culture 
consist in (1) greater ease in digging, (2) more efficient weed control by 
covering rather than by removing and disturbing the root system close to 
the row, (3) more friable soil for tuber development, (4) protection of tubers 
from the spores of the late-blight fungus {Phytophthora infestans), and (5) 
greater surface evaporation of moisture, a factor of special value on heavy 
soils in regions of possible excess, or poorly distributed, growing-season 
rainfall. 

Geismar (1905) compared hill and level culture on both fall- and spring- 
planted potatoes. His yields favored level culture for both the fall- and 
the spring-planted crops by 5 and 7 per cent increases, respectively. Geis- 
mar very mistakenly added these increases and credited the total to the 
advantage of level culture. This was a blight year at the Michigan 
station, and, altho Geismar stated that the damage from the disease was 
confined to the tops, it is possible that some protection from ridging was 
furnished the ridged plots, and that in a dry year the advantage in level 
culture would have been even greater. Stone (1905), at the Cornell 
station, compared various frequencies of hilled and level culture for five 
years on medium light soil. In each of these years, the yields were best 
under level culture, the differences ranging from 1 to 37 bushels per acre, 
the average favoring level culture by 14 bushels. Stone did not explain 
why the smallest differences in yield occurred in the two driest years, when 
the greatest advantage from level culture might have been expected. 
During three of these five years, he compared continuous level culture up 
to nine cultivations, with laying by and ridging the crop after from three 
to five cultivations. In these tests, the continuous level culture gave an 
average advantage of 54 bushels per acre. Shepperd and Churchill 
(1911), altho reporting no data, stated that level culture has given far better 



A Study of Factors Influencing the Yield of Potatoes 1245 

results than ridging in North Dakota, even in sections having the heaviest 
rainfall. 

Since the system of cultivation as well as the depth of planting may have 
a part in determining the ultimate depth of the seed piece, this factor of 
depth of seed piece should be controlled in all tests of the influence of system 
of cultivation on yield. Woods and Bartlett (1909) and Woods (1911) 
reported a comparison of the yields from shallow planting and high ridging 
and from medium planting and medium ridging. In these tests the depth 
of seed piece was constant. The medium-ridge culture gave a three- 
years average yield of 10 bushels per acre more than the high-ridge culture. 
Woods (1914), reporting a continuation of these tests but including deep 
planting and level culture, showed a four-years average yield for the years 
1910 to 1913, inclusive, of 276 bushels per acre from medium ridging, 261 
bushels per acre from level culture, and 232 bushels per acre from high 
ridging. Thus, over a long period of years, in a region of relatively high 
rainfall and with the depth of seed piece constant, the yields favored a 
system ranging from medium-ridge to level culture. Because of the 
greater difficulty of harvesting the crop from level culture, however, Woods 
concluded that, for Maine conditions of soil and climate, there is little 
choice between these three methods. 

Macoun (1905) reported four-years average yields, from level and from 
ridge culture, favoring ridge culture by 22 bushels per acre. Level culture 
proved the better in one of the four years, and, altho one of the four was 
a drought year, this was not the year in which the level culture yielded 
the best. Macoun's results were obtained at the Ottawa station, in a moist 
sandy loam not subject to drying out. Zavitz (1916), in a nine-years 
test, obtained an average difference of 7.6 bushels per acre in favor of ridge 
culture. He stated that three of the nine years were comparatively dry, 
and in these three years level culture gave the higher yields. Clinton 
(1916), in a six-years comparison of ridge and level culture, obtained yields 
slightly favoring ridge culture during three years and yields slightly favor- 
ing level culture during the remaining three years. He concluded that 
the only difference in the influence of these two systems on yield is in an 
advantage from a lower percentage of blight rot under the ridge-culture 
system. 

It must be concluded from the above review of experiments that, in 
general, level culture has given slightly better yields than has ridging. 
The advantage has been most marked in dry years and in the hghter 
soils. Depending on regional soil type and seasonal rainfall, however, 
the advantages generally conceded to ridging should be considered in choos- 
ing the best system to fit a specific localit3^ 

Owing to the lack of variation in tillage methods within each of the 
regions studied, it was not possible to correlate this factor with yield by 
survey methods. Altho some variation in the degree of ridging exists 



1246 Earle V. Hardenburg 

within each region, lack of information on a definite measurement of this 
degree makes its use in these studies impossible. 

Level culture is the system generally understood to be practiced on Long 
Island. However, nearly all the growers there, while maintaining level 
culture thruout most of the season, cultivate a slight ridge toward the row 
late in the season, at either the last or the last two cultivations. The 
reasons given by growers of the 1912 crop for this practice, were (1) that 
digging was made easier and (2) that the tubers were protected from the 
spores of the late-blight fungus. Altho the potato soils of Long Lsland are 
relatively light in texture, the growing-season rainfall of this region, as 
shown in figure 127 (page 1149), is relatively high. All growers of the 
1912 crop reported the practice of level culture. 

In Steuben County a system of relatively high ridging is practiced. A 
ridge is gradually worked toward the row at each cultivation thruout the 
season, and this is increased late in the season by a speciahzed implement 
called a hiller. Because of the heavy soil of this region, ridge culture is 
doubtless of some merit due to the greater ease in harvesting and the 
protection from blight rot which it affords. All the growers whose 1912 
crop was studied practiced ridge culture. 

Of the 300 growers in Monroe County, 272 reported the practice of 
level culture, with a slight ridging toward the end of the growing season. 
The other 28 growers in this region practiced continuous level culture in 
1913. 

Only 1 of the 300 growers in Franklin and Clinton Counties practiced 
level culture in 1913. Ridging is here begun as soon as the crop is up, 
the tops, and such weeds as have grown since planting, being covered at 
that time. By the end of the growing season an extreme ridge has been 
developed, greater than that used in Steuben County. Altho the grow- 
ing-season rainfall of this region is almost as high as that of Long Island, 
the light soils which prevail in most of the section do not seem to warrant 
such extreme ridging. This is a problem apparently impossible of solution 
by survey methods and one requiring years of test. 

FREQUENCY OF CULTIVATION 

Cultivation as a prime requisite of good crop yields thru its resulting 
in weed control, moisture conservation, and increased availability of plant 
food, is one of the oldest known practices of agriculture. However 
very few experiments of value have been conducted for the express pur- 
pose of determining the optimum frequency of cultivation. The value 
of such tests is, of course, dependent on such other factors as duration of 
the experiment, condition of the seed bed, replication, and time of cultiva- 
tion. Conclusions drawn must give due consideration to the available 
soil moisture and fertility and the soil type under which the test is 
conducted. 



A Study of Factors Influencing the Yield of Potatoes 1247 

Stone (1905), in a carefully controlled experiment covering six years 
at the Cornell station, compared the yields of potatoes from cultivating 
three, four, five, six, seven, eight, nine, eleven, and thirteen times during 
the season. During these years he obtained average yields favoring 
seven, eight, and nine cultivations, by from 8 to 100 bushels per acre. 
The plots were replicated from two to four times. Stone's tests showed 
clearly that under the conditions of his experiment it was possible to culti- 
vate beyond the limit of maximum production. Emerson (1907) compared 
yields from what he called poor, medium, and thoro cultivation. Under 
poor tillage, the land was harrowed three times and cultivated twice, the 
land not being kept free from weeds even early in the season. Under 
medium tillage, the land was harrowed three times and cultivated four 
times, the weeds growing only in the rows after the crop was nearly ripe. 
Under thoro tillage, four harrowings and six cultivations were given, no 
weeds being allowed to grow. The yield of the medium-cultivated crop 
exceeded that from poor tillage by 60 per cent and that from thoro tillage 
by about 9 per cent. Emerson concluded (1) that tillage can be overdone, 
(2) that cultivation to control weeds only is sufficient, and (3) that, in 
eastern Nebraska, two or three harrowings and five or six cultivations are 
sufficient for potatoes. 

The high frequency of cultivation recorded for some of the regions 
included in this study must not be construed to mean that this frequency 
applies only to operations with a cultivator. As already explained, all 
operations which stir the soil and control weeds after planting are included. 
Inasmuch as the rate of planting and the value of manure and fertihzer 
have already been shown to be very influential on yield, frequency of 
cultivation is here studied for each region in connection with these factors. 

Frequency of cultivation on Long Island 
Long Island is the only region, of the four surveyed, in which the Hal- 
lock weeder is used extensively. This implement is used principally just 
before or just after the crop comes up. Having a broad sweep, it removes 
very efficiently those small weed seedlings which develop between planting 
time and the time at which the plants come up. Since the entire crop in 
this region is planted in drills, cross cultivation is impossible and much 
hand hoeing is therefore done to remove the weeds that develop during 
the growing season. Many growers reported also hand pulling of weeds. 
These operations, in addition to the usual cultivations between the rows, 
resulted in the highest frequency of cultivation in this region, the average 
in 1912 being 10.9 times. 

The relation of this factor to yield, under constant rates of {planting, 
is shown in table 75. The averages for the 329 farms listed in this table 
indicate that in 1912 it did not pay to cultivate more than ten times. 
In fact, these averages seem to indicate that frequency of cultivation above 



1248 



Earle V. Hardenburg 



TABLE 75. Relation of Frequency of Cultivation and Rate of Planting, to Yield, 
ON 329 Long Island Farms in 1912 









Amount of seed planted 






Number of times 


Less than 12 
bushels 


From 12 to 14 
bushels 


14 bushels and 
more 


Average 


cultivated 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Less than 10 

10-13 


44 
59 
35 


183.7 
158.7 
155.7 


42 
52 
32 


165.5 
183.9 
157.4 


28 
24 
13 


190.9 
194.1 

222.8 


114 
135 

80 


176.6 
177 1 


13 and more 


168.6 


Total 


138 




126 




65 




329 








Average 




166.2 




170.2 




197.8 




175 7 









ten was not influential on yield. A further study of the table, however, 
shows that as the rate of planting increased, the efficiency of the higher 
frequencies of cultivation increased. This phenomenon may possibly 
be explained })y considering it in connection with the figures in table 76, 



TABLE 76. Relation of Frequency of Cultivation and Value of Manure and Ferti- 
lizer, TO Yield, on 330 Long Island Farms in 1912 





Value of manure and fertilizer- 


Number of times 


Less than $30 


From $30 to $40 


$40 and more 


Average 


cultivated 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Less than 10 

10-13 

13 and more 


32 
57 
40 


175.3 
155.7 
151.1 


65 
62 
26 


181.2 
191.2 
163.1 


18 
16 
14 


166.5 
191.9 
217.9 


115 
135 
80 


178.4 
177.1 
168.6 


Total 129 




153 




48 




330 




Average 




158.7 




182.2 




194.4 




175.5 



showing the relation of frequency of cultivation and value of manure 
and fertilizer to yield. The variation in the average yields in tables 75 



A Study of Factors Influencing the Yield of Potatoes 1249 

and 76 exhibits a very obvious similarity. It is evident in both tables 
that more than ten cultivations were efficient only when the greater 
amounts of seed and of manure and fertilizer were used. This may 
indicate either that a greater amount of tillage was necessary to control 
the greater weed growth produced by the increased fertility, or that 
more tillage was necessary to make available sufficient plant food to 
support the increased stand of potatoes. It may be concluded that, on 
the average, it did not pay to cultivate potatoes more than ten times in 
this region in 1912. The coefficient of correlation between this factor 
and yield, as shown in figure 145, is - 0.087 ± 0.037. This shghtly 



§ 



Yield per acre, in bushels 

g 15 8 S 



r-l O ^ 



^ 



3- 4 
5- 6 

7- 8 
9-10 
11-12 
13-14 
15-16 
17-18 
19-20 
21-22 
23-24 
25-26 
27-28 





1 














_ 














1 


2 




3 


1 


2 


1 








1 


5 


5 


19 


3 


11 


11 


6 


3 






1 


1 


11 


9 


17 


10 


17 


8 


7 


3 




1 




1 


6 


10 


20 


17 


18 


2 


6 


4 


4 


2 




1 


3 


10 


11 


5 


6 


4 


1 


2 


3 








2 


2 
1 


5 
5 

1 
1 


6 
1 

1 


2 

2 

1 


1 


1 




1 






1 























23 



13 



8 



1 

10 

64 

85 

90 

46 

19 

10 

1 

2 

1 



1 

330 



1 6 27 38 81 43 60 27 
r = -0.087± 0.037 
Fig. 145. correlation of frequency of cultivation and yield on 330 long island 

FARMS IN 1912 



negative value indicates that the average frequency was a little too high 
for maximum production. However, the relatively high probable error 
renders the coefficient insignificant. 

Frequency of cultivation in Steuben Comity 
Cultivation was not so thoroly practiced in Steuben County in 1912, as 
on Long Island, the average frequency being 7.6 cultivations. Weed 
control is much more of a problem here than elsewhere because of the 
fact that potatoes are usually grown on sod land of several 3^ears standing 
and on land containing a considerable quantity of weed seed or stubble. 
Furthermore, the seed bed is here more poorly prepared than in most 
other regions because of the susceptibility of the soil to extreme puddling. 
Under these conditions, the factor of frequency of cultivation would be 



I 



1250 



Earle V. Hardenburg 



expected to have a direct positive influence on jaeld. The relationship of 
this factor and the rate of planting, to yield, is shown in table 77: 



TABLE 77. Relation of Frequency of Cultivation and Rate of Planting, to Yield, 
ON 349 Steuben County Farms in 1912 





Amount of seed planted 


Number of times 
cultivated 


From 6 to 10 
bushels 


From 10 to 14 
bushels 


From 14 to 18 
bushels 


Average 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


1-4 


78 f: 
67 

2 


122.5 
123.5 
108.3 


70 
97 
15 


135.6 
141.5 
164.2 


4 
10 
6 


168.6 
201.3 
192.1 


152 
174 
23 


130.3 


4-7 


138.0 


7-13 


168 4 






Total 


147 




.182 




20 




349 








Average 




122.8 




141.4 




191.3 


.... 


136.4 



Four of the groups studied in table 77 contain too few farms to give 
reliable results, yet the study shows clearly enough that the average yields 
increased as the frequency of cultivation increased, irrespective of the 

TABLE 78. Relation of Frequency of Cultivation and Value of Manure 
AND Fertilizer, to Yield, on 147 Steuben County Farms in 1912 









Value of manure and fertihzer 








From 14 to $12 


From $12 to $20 


From $20 to $50 


Average 


cultivated 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


1- 4. . 


23 
35 
10 


136.5 
142.4 
166.0 


20 

24 

4 


150.1 
172.5 
169.9 


5 

21 

5 


165.9 
165.7 
173.5 


48 
80 
19 


145 


4- 7 . 


157 


7-13 


168.4 






Total 


68 




48 




31 




147 








Average 




145.0 




162.9 




167.1 




155.1 



A Study of Factors Influencing the Yield of Potatoes 1251 

rate of planting. To further allay suspicion that the increased yields, 
apparently due to increased cultivation, were not in part due to corre- 
sponding increases in the value of manure and fertilizer, a study of this 
factor in connection with value of manure and fertilizer is presented in 
table 78. Altho comparatively few farms are involved in the study in 
this table, the positive influence of frequency of cultivation on yield 
is well shown. In contrast to Long Island, it is apparent that growers 
in this region did not exceed the profitable limit in number of cultivations 
in 1912. This statement is further proved by the coefficient of correla- 
tion, 0.231 ± 0.034, shown in figure 146. 



Fig. 146. 



Yield per acre, in bushels 

lO O lO O lO 

M lO I^ O C-1 

-I rt ,-( (M (M 





eg 


lO 


f^ 


o 


S 


LO 


r- 


S 


oi fo 


1^ 


' O 


« 


lO 


















(M (M 


(M 


CO 


CO 


CO 


1 




2 
4 


1 
5 


2 
10 


1 
3 
10 


1 

10 


2 

1 














1 


2 


8 


9 


12 


17 


9 


10 


4 














2 


6 


18 


15 


11 


5 


5 






1 






1 




1 


5 


16 
6 


14 

7 


10 
16 


15 
5 


8 
2 


















1 


5 
2 


5 

6 


4 
4 


2 
2 


3 
4 


1 
1 




1 














1 


1 


1 


1 


1 


2 


















1 


1 


1 


2 


2 


1 


1 











11 

40 

73 

65 

69 

39 

23 

19 

8 

4 

1 

4 

1 







1 

2 5 26 64 73 78 52 38 9 10 2 1 360 
r = 0.231 ± 0.034 

CORRELATION OF FREQUENCY OF CULTIVATION AND YIELD ON 360 STEUBEN COUNTY 
FARMS IN 1912 



Frequency of cultivation in Monroe County 
The common rotation of one to two years of cultivated crops, followed 
by two years of grain, followed by only one to two years of hay, makes 
the problem of weed control less of a limiting factor to jdeld in Monroe 
County than in Steuben County. The growing-season rainfall for this 
region, however, as shown in figure 127, is lower than that for the other 
three areas, and, because of this, cultivation for moisture conservation 
might be presumed important. The average frequency of cultivation 



1252 



Earle V. Hardenburg 



in 1913 was 8.1 times. The relation of this factor, in connection with 
the rate of planting and the value of manure and fertilizer, to yield, is 
shown in tables 79 and 80, respectively: 



TABLE 79. 



Relation of Frequency op Cultivation and Rate op Planting, to 
Yield, on 300 Monroe County Farm.s in 1913 





Amount of seed planted 


Number of times 


Less than 12 
bushels 


From 12 to 15 
bushels 


15 bushels and 
more 


Average 




Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Less than 7 

7-9 


34 
41 
25 


117.1 
115.3 
113.2 


29 
30 
54 


117.9 
114.4 
133.6 


15 
23 
21 


112.1 
145.6 

172.5 


76 
124 
100 


116.6 
120.8 


9 and more 


138.8 


Total 


100 




143 




57 




300 








Average 




115.4 




122.7 




150.1 .... 


126.2 



TABLE 



Relation of Frequency of Cultivation and Value op Manure and- 
Fertilizer, to Yield, on 300 Monroe County Farms in 1913 





Value of manure and fertilizer 


Number of times 
cultivated 


Less than $10 


From $10 to $20 


$20 and more 


Average 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Less than 7 

7-9 

9 and more 


36 
59 
41 


106.8 
114.2 
120.6 


33 

56 

47 


122.6 
125.9 
150.1 


7 
9 
12 


137.6 
133.9 
159.2 


76 
124 
100 


116.6 
120.8 
138.8 


Total . 


136 




136 




28 




300 








Average 




114.4 




134.3 




145.5 




126.2 



Altho increased frequency of cultivation did not produce increased 
yields for growers using less than 12 bushels of seed per acre, this does 



A Study of Factors Influencing the Yield of Potatoes 1253 

not apply to the growers who used more seed. Furthermore, since the 
group of growers using less than 12 bushels of seed per acre included those 
who planted in checkrows, it was doubtless possible to control weeds 
with fewer cultivations than were necessary for fields planted in drills. 
A fairly consistent positive influence of frequency of cultivation on yield, 
irrespective of the value of manlire and fertihzer used, is shown in table 
80. It is evident that the highest frequencies of cultivation were pro- 
ductive of profitably increased yields except for the few growers who, 
because of checkrow planting which made cross cultivation possible, were 
able to control the weeds with fewer cultivations. The coefficient 0.169 
± 0.038 (fig. 147), while small, is positive and is significant in value. 



t- o 



Yield per acre, in bushels 

>1 g t2 I I 

" S I 2 2 







1 


1 


1 
















1 1 




5 


6 


4 




3 












1 


10 


16 


8 


9 




2 


2 










1 


9 


14 


8 


12 




4 


1 


3 








1 


10 


16 


14 


14 




6 


2 










2 


4 




6 


7 




4 


1 








1 


1 


1 


7 


3 


4 




3 








1 






2 


3 




4 




1 


1 


1 


1 








2 


1 


1 
2 

1 


1 
2 
2 

1 




1 


1 











1 7 38 70 50 61 34 24 8 4 1 1 1 300 
r = 0.169 ±0.038 
Fig. 147. correlation of frequency of cultivation and yield on 300 monroe county 

FARMS IN 1913 



Frequency of cultivation in Franklin and Clinton Counties 
Cultivation in Franklin and Clinton Counties is not generally continued 
as late in the growing season as in most other regions of the State. On 
the other hand, ridging is begun early in the season and the crop is given the 
final ridging soon after blossoming. The average number of cultivations 
in this region in 1913 was 6.3. As shown in table 15, this was the only 
region of the four in which a very significant proportion of the total acreage 



12.54 



Earle V. Hardenburg 



was plowed in the fall. This practice allows earlier and better seedbed 
preparation in the spring than would otherwise be possible, and makes 
later cultivations during the growing season less necessary. The relation 
of this factor in connection with the amount of seed and the value of manure 
and fertihzer used, to yield, in 1913, is shown in tables 81 and 82, respec- 



ABLE 81. 



Relation of Frequency of Cultivation and Rate of Planting, to Yield, 
ON 300 Franklin and Clinton County Farms in 1913 









Amount of seed planted 






Number of times 


Less than 12 
bushels 


From 12 to 14 
bushels 


14 bushels and 
more 


Average 




Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Less than 6 

6-8 


46 
41 
38 


164.1 
162.5 
159.6 


49 
35 
20 


184.0 
192.0 
191.2 


30 
30 
11 


189.0 
204.8 


125 
106 


177.2 

187.7 


8 and more 


184.5 69 


172.0 


Total .... 


125 




104 




71 


300 








Average 




162.1 




188.1 




195.0 




179.3 



TABLE 82. Relation of Frequency of Cultivation and Value of Manure and 
Fertilizer, to Yield, on 297 Franklin and Clinton County Farms in 1913 









Value of manure and fertihzer 






Number of times 
cultivated 


Less than $10 From $10 to $14 i $14 and more 


Average 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Less than 6 

6-8 


44 
31 
19 


173.0 

177.7 
142.5 


41 

38 

27 


177.5 38 
188.4 1 37 
177.0 1 22 


189.0 

188.4 
188.9 


123 
106 
68 


179.1 
185.2 


8 and more 


171.5 


Total 


M 




106 


1 97 




297 








Average 




168.2 




181.3 .... 


188.7 




179.5 



A Study of Factors Influencing the Yield of Potatoes 1255 

lively. As shown in these tables, there was no apparent gain in yield in 
J913 from cultivating more than seven times. In fact, it is question- 
able whether the small gain shown in most cases from cultivating more 
than five times was sufficient to pay the extra cost of the labor involved. 
This means that the average frequency for the year concerned was not far 
from optmium. The coefficient 0.055 ± 0.039 (fig. 148), while positive, is 



Yield per acre, in bushels 



8 



?i 



^ ^ 



i 


o 
4 


> 


5 








6 




7 


§ 


8 


•^ 


9 


o 


lU 


Lh 


II 


^ 


12 


^ 


13 
14 



t^ 


o 


^ 


iQ 


t^ 


S 


^ 


CM 


(N 




1 




3 


1 


3 


2 








10 


2 


3 


4 


9 


6 


5 


3 






32 


3 


5 


14 


17 


15 


18 


5 


4 


,9 


83 


3 


4 


12 


7 


19 


5 


9 


2 


3 


64 


1 


4 


6 


8 


16 


2 


3 


2 




42 


1 


5 


6 


3 


8 


3 


2 


1 




29 




5 


2 


3 


1 


1 




3 




15 




1 


2 


3 


2 


1 




1 




10 


1 






1 


1 




1 






3 

1 






1 




3 

2 


1 


1 
2 


1 




6 
5 



12 27 



50 



26 



14 



300 



52 76 38 
r = 0.055 ± 0.039 
Fig. 148. correlation of frequency of cultivation and yield on 300 franklin and 
clinton county farms in 1913 

too small and insignificant to indicate any real correlation of frequency of 
cultivation with yield. It must be concluded, therefore, that in practically 
all cases sufficiently frequent cultivation was given so that it was not a 
factor limiting yield. 



Spraying as a factor in potato production must have been first practiced 
in this country sometime after 1859. This is the date when the Colorado 
potato beetle (Leptinotarsa decemlineata) began its movement eastward from 
the Rocky Mountains (Fraser, 1912). The potentiahty of this pest to 
cause complete defoliation has since resulted in the extensive use of such 
arsenical insecticides as paris green, arsenate of lead, and arsenite of 
soda, for its control. The extent to which insecticides have been used in 
a given locality has depended on the prevalence of the beetles. The fact 
that growers in a certain locality did not spray for insects during a certain 
season, is evidence that insects were scarce or ahiiost absent. A study of 
the influence of spraying with insecticides on yield in a given region, there- 



I 



1256 Earle V. Hardenburg 

fore, may not be expected to show positive results. On the contrary, 
positive influence on the yield from spraying with a fungicide for th^ 
simultaneous control of late blight {Phytophthora infestans), early blight 
(Alternaria solani), and tipburn, as well as for the control of flea beetles 
(Epitrix cucumeris), may be expected in most potato regions every year 
if the spraying is done thoroly. As a standard fungicide, bordeaux mix- 
ture has been used for this purpose for about thirty-six years, the practice 
having begun in France in 1885 (Macoun, 1905). Probably the first 
systematic and continuous series of spraying experiments with bordeaux 
conducted in this country, were begun by Jones at the Veimont station 
in 1891. Lutman (1911) has reported a twenty-years summary of these 
experiments. During this period, late blight occurred fifteen years out of 
the twenty, the loss in yield from the resulting rot varying from year to 
year. These tests showed a gain in yield every year from spraying, the 
percentage of gain per acre ranging from 18 in a year of no blight, to 215 
in a year of much blight, and the average gain per acre for the twenty 
years being 64 per cent. Altho the frequency of spraying in these tests 
varied from one to five times a season, the influence of spraying cannot be 
studied because different frequencies were not used within any one year. 

Second in importance to the Vermont experiments are those of ten 
years duration conducted by the New York station at Geneva, under the 
direction of Stewart, French, and Sirrine (1912). These tests were dupli- 
cated, one series being conducted on heavy clay loam soil at Geneva, and 
the other on light sandy loam soil at Riverhead. During the test, late 
blight occurred six years out of the ten at Geneva and only three years out 
of the ten at Riverhead. As might be expected, therefore, the greater 
average gain from spraying was obtained from the Geneva plots. How- 
ever, there was not one year out of the ten on either series of plots in which 
a gain from spraying was not obtained. In years of no blight this gain 
was attributed to the control of such factors as flea beetles, early blight, 
bugs, and tipburn. Spraying every two weeks during the growing season 
was each year compared to spraying but three times. With but one slight 
exception, the more frequent spraying resulted in the higher yield. The 
ten-years average difference in yield due to this difference in frequency of 
spraying was 28.5 bushels per acre for Geneva, and 20.7 bushels per acre 
for Riverhead. Spraying every two weeks gave a ten-years average gain 
in yield of 97.5 bushels per acre at Geneva and 45.7 bushels per acre at 
Riverhead. 

Clinton (1916) reported the results of spraying in a thirteen-year s 
test at the Connecticut station. Altho no data are presented on the 
influence of the various frequencies of spraying, increased yields ranging 
from 10 to 101 bushels per acre (the average being 38 bushels per acre) 
were reported. At this station, also, increased yields due to spraying were 
obtained every year, including years of no bhght, in which the average 



A Study of Factors Influencing the Yield of Potatoes 1257 

increase was 29 bushels per acre. In all but four of twenty-two tests, the 
increased yield more than paid the cost of spraying, the average net gain 
per acre being $15. 

Stone (1905) varied the frequency of bordeaux spraying from year to 
year in a six-years experiment in which imsprayed checki'ows were used. 
But he did not vary the frequency between plots in any single year. There- 
fore, no data on frequency of spraying, of any value, are available from this 
source. A gain in yield from spraying, ranging from 7 to 83 bushels per 
acre, was obtained during five of the six years. Stone did not attempt to 
explain the one year of loss apparently clue to spraying, altho the loss 
averaged more than 30 bushels per acre. 

Somewhat conflicting data were obtained by Sandsten and Milward 
(1906) in a two- plot experiment of one year duration. Comparing the 
results from two, three, five, and six applications of bordeaux to each 
plot, they found, on one plot, a constant increase in yield with each increased 
application up to and including five, the increase dropping off slightly 
with six applications. The second plot showed a general tendency for 
yields to increase with the frequency of applications, but the data are 
inconsistent, three applications resulting in a yield lower than that of the 
check plot, while five applications resulted in a 172-per-cent increase. 

Testing the influence of frequency of spraying on yield in a blight-free 
year, Kohler (1909) compared yields from plots duphcated four times and 
sprayed two, three, four, and six times, respectively. His results showed 
a decrease in yield of marketable tubers, of 0.7 bushel per acre, from 
spraying two times, and increased yields of 8.4, 15.8, and 18.7 bushels per 
acre, respectively, from spraying three, four, and six times, as compared 
to check plots. A year later, when again there was no occurrence of blight, 
Kohler (1910) obtained an average increase in yield of 17.4 and 18.8 
bushels per acre over the yields of the unsprayed plots, from four and six 
applications, respectively. Kohler therefore concluded that, irrespective 
of late blight, better yields may be expected from sprayed plots because of 
the healthier condition of the foliage. 

The value of thoroness in applying bordeaux has been well demonstrated 
by Zavitz (1916) in his report of a seven-years test at the Ontario station. 
In five of the seven years, no blight rot occurred. In spite of this, both 
total and marketable yields increased directly with the frequency of 
spraying, in spraying three, four, and five times during each of the five 
years. Zavitz found that spraymg both the tops and the bottoms of the 
plants in all three applications, rather than spraying only the tops, gave 
an increase in total yield of 13.5 bushels per acre, thus demonstrating the 
value of thoroness. In 1910, a year of blight rot, spraying from^two to 
six times gave a proportionate increase in the yield of sound potatoes, a 
constant increase in the length of the growing period of the plants, and a 
constant decrease in the percentage of rot in the crop. 



1258 



Earle V. Hardenburg 



Macoun (1905) did not test the influence of frequency of spraying, but by 
spraying four tinies in 1901 and in 1902, and five times in 1904, he obtained 
an average increased yield, for the three years, of 94.5 bushels per acre. 

In spite of the loss of millions of dollars to the growers in New York 
caused by the occurrence of blight every two or three years, and in spite of 
the proved value of bordeaux mixture as a preventive of this disease, rela- 
tively few growers make a practice of using a fungicide. Altho blight 
has frequently been epiphytotic in all four of the regions surveyed except 
Franklin and Clinton Counties, only one-third of the growers on Long 
Island in 1912, 5 per cent in Steuben County in 1912, and 25 per cent 
in Monroe County in 1913, sprayed their crops with a fungicide. 
Occasional attacks of blight have been observed in Franklin and Clin- 
ton Counties, but epiphytotics are practically unknown; and even when 
the fungus is present on the foliage, it seldom attacks the tubers to any 
serious extent in this region. Only 1 per cent of the growers in this region 
sprayed for blight prevention in 1913. So few growers used fungicide in 
Steuben, Monroe, and Franklin and Chnton Counties, that the influence of 
frequency on yield could not be studied in detail. The extent to which 
insecticides and fungicides were used in the four regions, and the average 
yields per acre under the various treatments, are given in table 83. In 

TABLE 83. Summary of Spraying in the Four Regions Surveyed 





Long Island, 
1912 


Steuben County, 
1912 


Monroe County, 
1913 


Franklin and 

Clinton Counties, 

1913 


Treatment 


Per 

cent 

of 
farms 


Average 

yield 
per acre 
(bushels) 


Per 

cent 

of 
farms 


Average 

yield 
per acre 
(bushels) 


Per 

cent 

of 

farms 


Average 

yield 
per acre 
(bushels) 


Per 

cent 

of 
farms 


Average 

yield 
per acre 
(bushels) 


No spraying 

Insecticide only 


3 

64 
33 


190.7 
161.7 
197.1 


51 

44 

5 


130.2 
137.3 

171.5 


12 
63 

25 


150.3 
121.5 
126.2 


36 

63 

1 


186.1 
177.3 
152.3 






Average 


100 


175.5 


100 


136.4 


100 


126.2 


100 


179.3 







this table, a reliable criterion of the beneficial effects of spraying with fungi- 
cide is not evident in those cases in which the percentage of growers 
following any one of the three practices was below 15. 

Spraying on Lo7ig Island 

Spraying was done to a greater extent on Long Island than in the other 

three districts surveyed. Only 9 growers out of 316 did not spray at all in 

1912. About one-third of all the growers used a fungicide for the control 

of blight, tipburn, and flea beetles. Ten per cent of the growers reported 



A Study of Factors Influencing the Yield of Potatoes 1259 



their crops affected with bhght, while nearly one-fourth reported flea- 
beetle injury. The spraying practices and the average yields, together 
with the amount of seed and the value of the fertilizer used, are given 
in table 84. The number of growers not spraying at all was too small 



TABLE 84. 



Relation of Spraying Practice to Yield on 316 Long Island Farms in 
1912 



Spraying practice 


Number 
of farms 


Average 

yield 
per acre 
(bushels) 


Average 
amount of 
seed used 
per acre 
(bushels) 


Average 

value of 

manure and 

fertilizer 


No spraying 


9 
204 
103 


190.7 
161.7 
197.1 


12.2 
11.8 
13.5' 


S33.08 


Insecticide only .... 


31.42 


Fungicide . . 


33.65 








316 




















175.3 


12.5 


$32.27 









to allow of attaching any significance to the average yield obtained by 
these growers. The increase in yield per acre of over 35 bushels, resulting 
from the use of a fungicide rather than an insecticide, is significant, altho a 
part of this difference in yield was due to the use of more seed and fertilizer. 
Results of further studies on the influence of frequency of spraying with 
fungicide, on yield, are shown in tables 85 and 86, in which the factors of seed 



TABLE 85. 



Relation of Number of Times Sprayed with Fungicide, and Rate of 
Planting, to Yield, on 109 Long Island Farms in 1912 





Amount of seed planted 


Number of times 


Less than 12 
bushels 


From 12 to 14 
bushels 


14 bushels and 
more 


Average 


sprayed 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Less than 5 

5-7 


11 
11 

4 


154.6 
197.2 
217.2 


15 
19 

8 


189.7 
196.5 
197.5 


7 
18 
16 


181.5 
197.0 
220.5 


33 

48 
28 


179.5 
196.9 


7 and more 


213.8 


Total 


26 




42 




41 ■ 




109 








Average 




187.5 




194.2 


.... 


201.6 




196.8 



1260 



Earle V. Hardenburg 



TABLE 



Relation of Number of Times Sprayed with Fungicide, and Value of 
Manure and Fertilizer, to Yield, on 109 Long Island Farms in 1912 





Value of murane and fertilizer 


Number of times 


Less than $30 


From $30 to $40 


$40 and more 


Average 


sprayed 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Num- 
ber of 
farms 


Average 

yield 
per acre 
(bushels) 


Less than 5 

5-7 


15 
13 
2 


161.4 

182.8 
170.0 


12 
25 
17 


177.9 
202.8 
191.3 


6 
10 
9 


236.3 
188.6 
248.6 


33 

48 
28 


179.5 
196.9 


7 and more 


213.8 


Total 


30 




54 




25 




109 








•Average 


.... 


170.0 




195.4 




228.1 




196,8 



and fertilizer, respectively, are separated. It appears from table 85 that 
the yield increased directly with the frequency of spraying, irrespective 
of the rate of planting. In table 86, the influence of frequency of spraying 
does not appear to have been so marked. This is due partly, however, 
to the insufficient number of growers in some of the groups. As a whole, 
these data indicate that the growers who sprayed the greatest number of 
times, obtained at least enough increase in yield to pay the extra cost 
of the labor and materials involved. The correlation of frequency of 
bordeaux spraying with yield is further shown in figure 149. The coeffi- 



Yield per acre, in bushels 



8 



^ X 











?r 






o 


^) 


u3 




o 
















(M 




(M 










1 


1 


1 


9 




1 






1 












2 


3 


5 


1 




2 


1 








1 




3 


2 


4 












1 






1 




3 


4 


3 


3 






1 






1 




3 


3 


4 


3 


2 


1 


2 


1 






1 




5 

1 


2 
2 


5 
3 


2 


4 


2 




1 






1 




1 


1 


2 




2 


1 




















1 






1 









16 



11 



18 27 
r = 0.133 zt 0.065 
Fig. 149. correlation of frequency of bordeaux spraying, 
island farms in 1912 



11 6 5 3 1 

and yield, on 105 Loi 



A Study of Factors Influencing the Yield of Potatoes 1261 



cient, 0.133 ± 0.065, while positive, is not significant because of the 
relatively high probable error. Since all factors influencing yield are 
involved in this correlation, such a coefficient need not detract from the 
real measure of efficiency of bordeaux spraying. Much of interest regard- 
ing the actual practice of spraying thruout the region may be observed 
in the frequency table shown in figure 149. 

Spraying in Steuben County 
The year 1912 was a year of blight epiphytotic in Steuben County, many 
of the growers reporting more than half their crop left rotted and un- 
harvested in the field. More than 93 per cent of the growers found that 
the late-blight fungus affected either tops or tubers, or both. Such con- 
ditions should afford excellent means for determining the influence of 
frequency of bordeaux spraying on yield. The practice of spraying in 
this region in 1912, the average yield, the rate of planting„and the value 
of maniu'e and fertilizer per acre, are shown in table 87. The two facts 



TABLE 87. 



Relation of Spraying Pbactice to Yield on 360 Steuben County Farms 
IN 1912 



Spraying practice 


Number 

of 

farms 


Average 
yield 
per 
acre 

(bushels) 


Average 
amount of 
seed used 
per acre 
(bushels) 


Average 
value of 
manure 

and 
fertilizer 




184 

160 

16 


130.2 
137.3 
171.5 


9.9 
10.2 
11.5 


% 9.97 




10.23 


Fungicide 


' 12.96 


Total 


360 




















136.4 


10.1 


$10.06 









most clearly set forth in this table are: (1) that, whereas less than half 
the growers of this region did any spraying in 1912, only about 4.5 per 
cent used a fungicide for blight control; and (2) that those growers who 
sprayed the most thoroly also used more seed and fertilizer per acre than 
the average, and obtained correspondingly higher jaelds. 

Spraying in Monroe County 
The treatment accorded the potato crop for blight, tipburn, and flea- 
beetle control in Monroe County in 1913 is shown in table 88. These 
data indicate no advantage whatever, as to yield, from fungicidal spraying 
in 1913. Evidently there was none. The explanation doubtless lies in 
the fact that the principal functions of bordeaux mixture lie in the protec- 
tion of the tubers from blight rot and in the prolongation of the plant's 



1262 



Earle V. Hardenbitrg 



TABLE 88. Relation of Spraying Practice to Yield on 2S2 Monroe County Farms 

IN 1913 



Spraying practice 


Number 

of 

farms 


Average 
yield 

per 

acre 
(bushels) 


Average 
amount of 
seed used 
per acre 
(bushels) 


Average 
value of 
manure 

and 
fertilizer 




33 

177 

72 


150.3 
121.5 
126.2 


12.2 
12.2 
13.3 


$11 40 




11 07 




11 90 






Total 


282 
















Average . 




126.0 


12.5 


$11 33 









growing season, thereby increasing yield. The latter function naturally 
is asserted late in the growing season. In .1913, Monroe County ex- 
perienced one of the earliest killing fall frosts in its history. As a result, 
not only the bean crop, but the potato crop as well, was cut down, causing 
serious loss to the grower. Only about 7 per cent of the potato growers 
reported the occurrence of late blight up to the time of this frost. It is 
therefore evident that the possible advantages from fungicidal spraying this 
year were almost entirely nullified. Under these conditions, frequency of 
spraying could not be expected to shoAv a normal influence on yield. The 
correlation coefficient (fig. 150) is 0.084 ± 0.081. This shows insignificant 
correlation in respect to both the coefficient and its probable error. 



Yield per acre, in bushels 

O lO O LQ c 






^ ci 



s^ 



4 


3 


3 


4 


1 


1 




3 


8 


1 


4 


1 


1 


1 


1 


3 


2 


4 


3 


1 




1 





1 


3 


4 






1 


1 
1 




1 


2 






1 






1 









11 18 







7 17 11 3 
r = 0.084 ± 0.081 
Fig. 150. correlation of frequency of bordeaux spraying, and yield, on 68 monroe 

COUNTY FARMS IN 1913 



A Study of Factors Influencing the Yield of Potatoes 1263 



Spraying in Franklin and Clinton Counties 

As previously stated, the late-blight fungus (Phijtophthora infestans) 
seldom attacks the potato crop in Franklin and Clinton Counties. Very 
probably the reason for this is that muggy atmospheric conditions, 
so conducive to the disease, seldom prevail here after rains. On the 
contrary, wide spacing of plants and the frequent breeze that follows 
rain afford the plants ideal air circulation, thus preventing conditions 
favorable to blight. Only 3 per cent of the growers reported blight in 
1913. 

The extent to which spraying is practiced in this region is shown in table 
89. Altho the three growers who used fungicide used more than the 



TABLE 89. 



Relation of Spraying Practice to Yield on 273 Franklin and Clinton 
County Farms in 1913 



Spraying practice 


Number 

of 

farms 


Average 
yield 
per 
acre 

(bushels) 


Average 
, amount of 
seed used 
per acre 
(bushels) 


Average 
value of 
manure 

and 
fertilizer 


No spraying 

Insecticide only 


98 

172 

3 


186.1 
177.3 
152.3 


12.1 
11.8 
U.3 


•112 59 
13 29 




15.38 






Total 


273 




















179.9 


11.9 


$13 08 









average quantity of seed and fertilizer, they obtained less than the average 
yield. However, no significance can be attached to this fact, because of 
the extremely small number of farms. For this same reason, no correla- 
tion study of the frequency of spraying with the yield in this region has 
been made. 

relation of date of harvest to yield 

The date of harvest of the potato qrop is dependent on such factors as 
(1) the date of maturity of the crop, (2) the date of the first killing frost 
in the region, (3) the influence of early market prices, (4) the relation of 
the potato harvest to other farm work, and (5) the weather. The relative 
importance of each of these factors varies with the region, in New York 
State. There are sufficient experimental data available to prove that 
ordinarily the crop should not be harvested until the foliage is entirely 
dead because of natural maturity. The basis of this proof lies in the fact 
that the yield is increased rapidly during the last stages of growth of the 
plant. Jones (1899) tested the influence of the date of harvest on the yield 



1264 



Earle V. Hardenburg 



of potatoes planted on May 20, by digging every ten days from August 
2 to September 22. The yield increased from 30 bushels per acre on August 
2, to 353 bushels per acre on September 22. Of this increase, 119 bushels 
came after September 1, and 50 bushels developed during the last ten days. 
Kohler (1910), working with the variety Early Ohio planted on June 3, 
similarly tested the rapidity of development of the yield by digging about 
every seven days from July 31 to August 30. During that period, the 
foliage developed from an entirely green condition to complete maturity, 
and the marketable yield increased from 10.9 bushels to 226.8 bushels 
per acre. There was a gain in marketable yield, of about 7 bushels a day 
thruout the period, the yield increasing 44.7 bushels per acre during the 
last week. These data emphasize the possible mistake which some grow- 
ers make, of digging the crop prior to maturity in order to avoid unfavor- 
able weather or to take advantage of the relatively high early-market 
prices. 

It was not possible, for four reasons, to study by survey methods the 
influence of date of harvest on yield in the four regions surveyed. First, 
the information concerning the date of harvesting for Long Island was 
insufficient; secondly, about 93 per cent of the growers in Steuben County 
reported the crop more or less affected with late blight; thirdly, a large 
proportion of the growers in Monroe County reported a killing frost in 
1913 which cut down their crop exceptionally early, long before maturity, 
and reduced the yield much below the average; and fourthly, in Franklin 
and Clinton Counties the foliage is almost always killed by frost before 
it is mature, as was the case in 1913. The average date of harvest in 
the four regions for the years concerned in the survey, and the average 
date of the first killing fall frost for each region, are given in table 90: 

TABLE 90. Average Date of Harvest, and Average Date of First Killing Frost, 
IN THE Four Regions Surveyed 



Region 





Number 


Year 


of 




farms 


1912 


37 


1912 


348 


1913 


269 


1913 


295 



Average 
date of 
harvest 



Average date 

of first killing 

fall frost 



Long Island 

Steuben County 

Monroe County 

Franklin and Clinton Counties 



September 1 
September 27 
October 12 
September 24 



October 1-25 
October 5 
October 15 
October 1-10 



As is seen in table 90, the Long Island crop was harvested nearly a 
month before that of any of the other regions, the average date of planting 
being correspondingly earlier in this region due to climatic conditions. 
With the exception of Irish Cobbler and other early varieties grown in 
Nassau County, the crop in this district is usually mature before it is 
dug. These early varieties are often harvested and marketed before 



A Study of Factors Influencing the Yifld of Potatoes 1265 

maturity in order to reap the benefit of the early-market prices. Further- 
more, growers of early varieties in Nassau County harvest early in order 
to be able to follow the potato crop with a crop of vegetables or root crops 
for the fall market. A harvest of Cobbler potatoes in Nassau County, 
in the middle of July, is shown in figure 130 (page 1152). It can be noted 
that the foliage, as separated from the tubers, is not yet mature. On the 
following day this same field was ridged for turnip planting. 

As is evident from table 90, the Long Island crop is seldom affected by 
a killing fall frost. The Long Island growers aim to market their crop 
as soon after maturity as is possible, in order to supply the New York 
City market l^efore the earliest crop of other sections of the State is ready 
to harvest. For the years concerned in this study, the crop in the other 
three regions was harvested at an average date earlier than the average 
date of the first fall frost because of the severe blight epideinic of Steuben 
County, the early and severe frost in Monroe County, and the early 
frost in Franklin and Clinton Counties. Partly because of the tempering 
influence of Lake Ontario, the average date of harvest and the average 
date of the first fall frost in Monroe County are considerably later than 
for the other regions. Similarly, because of the influence of Lake Cham- 
plain, the growers located around Peru, in Clinton County, harvested their 
1913 crop approximately two weeks later than did other growers in the 
county. 

method of harvesting in the four regions surveyed 

The factors that ordinarily determine whether potatoes shall be dug 
by hand or by machine are, size of acreage, available labor supply, and soil 
conditions affecting the efficiency of machine diggers. The author (Har- 
denburg, 1915 a) found, for Steuben County in 1912, that when the 
potato acreage per farm was at least 5, the saving in labor cost by machine 
digging more than outweighed the interest, depreciation, and repair costs 
of digging by this method. Since the minimum acreage of potatoes per 
farm recorded in these studies was 5, the factor of economy in the use of 
machines for digging is probably of no concern in any of the other three 
regions. There are many farms in Steuben County with fields so steep 
as to limit the use of heavy elevator diggers. In 1912 the writer (Harden- 
burg, 1915 a) found the average slope of potato fields dug by hand to be 
somewhat steeper than that of machine-dug fields. A special type of 
digger, known as the Boss, or Keeler, which removes the tubers by a rotating 
reel, has been adapted to the hilly sections of Steuben County because of 
its exceptionally light draft and its adaptation to slopes too steep for elevator 
diggers. A study of the influence of slope of field on the type of digger 
used in 1912 in Steuben County revealed the fact that the fields dug with 
the reel digger had a higher average slope than those dug with the elevator 
type (Hardenburg, 1915a). 



]266 



Earle V. Hardenburg 



The method of harvesting, and the average potato acreage per farm, for 
the four regions surveyed, is shown in table 91. It is evident that the 



TABLE 91. 



Method of Harvesting, and Average Potato Acreage per Farm, 
THE Four Regions Surveyed 





Long Island, 
1912 


Steuben 
County, 1912 


Monroe 
County, 1913 


Franklin and 

CHnton 
Counties, 1913 


harvesting 


Per 

cent 

of 
farms 


Average 
potato 
acreage 


Per 

cent 

of 
farms 


Average 
potato 
acreage 


Per 

cent 

of 
farms 


Average 
potato 
acreage 


Per 

cent 

of 

farms 


Average 
potato 
acreage 


Elevator digger 

Reel digger 

Shovel plow shaker 
Hand . . 


84 
5 
5 
1 
5 


24.3 

21.8 
19.1 
41.6 


11 

48 

12 

23 

6 


17.0 
14.9 
13.4 
15.4 


71 


11 
3 

15 


12.9 

"l0'7' 
9.2 


15 

1 



76 

8 


8.0 
7.5 

6 9 


Various 




Average 


.... 


24.8 




14.7 




12.4 




7.2 



reel digger is not popular outside of Steuben County, probably decause this 
digger leaves the tubers in a more or less bruised and scattered condition. 
As indicated by the figures for both Long Island and Monroe County, 
the elevator digger was used extensively in these regions, where the soil 
is relatively light and the fields vary from rolling to level. Growers in 
Franklin and Clinton Counties have not used the elevator digger exten- 
sively because of relatively small acreages per farm and an abundance 
of large boulders, which make the use of such a digger next to impossible. 
More than three-fourths of the crop in this region was dug by hand 
in 1913. 

As a whole, the figures in table 91 show that the average acreage dug by 
hand was smaller than that dug by machine, and that the average acreage 
dug by the elevator digger was greater than that dug by any other type 
of machine. In cases of close planting and heavy top growth, it is often 
desirable to remove the tops from the tubers before picking them up. 
In figure 151, a view taken in Franklin County, two men are shown using 
forks for this purpose, behind an elevator digger drawn by four horses. 
This illustrates the necessity of using more than two horses because of 
the heavy draft of these machines. 

Three types of carriers were found in common use in the regions visited — 
the standard bushel slatted crate, a hamper basket, and fertilizer bags 
of various sizes. On Long Island, the commonest carrier in Suffolk 
County is the fertilizer bag, and that in Nassau County is the fertilzer 
bag supplemented by hamper baskets of about a bushel capacity. These 



A Study of Factors Influencing the Yield of Potatoes 1267 



.^iT- 




Fig. 151. removing vines from tubers to facilitate picking up the crop 



hampers as used in Nassau County, with the owner's initial painted on 
them, are shown in figure 152. This illustration shows also the common 
practice in this region of throwing from three to five rows together before 
picking up the tubers. The prime tubers are then picked up first, the 
culls remaining until later, as illustrated. Most of the crop of Nassau 
County — which is marketed directly from the field — is taken, either in 
those baskets or in bags, by wagon or motor truck, to the Wallabout 
Markets of Brooklyn, as shown in figure 153. In Suffolk County the crop 
is taken from the field mainly in bags and is hauled in them to the car or 
the storehouse, where the potatoes are dumped on the grader if they were 
not already graded when they were picked up, and are thence emptied 
into the car for shipment in bulk. 

The commonest carrier used in the other- three regions is the bushel 
crate, in which the crop is taken to storage, and there it is either dumped 
into piles or stored in the crate. B}^ far the greater part of the crop is 
stored in bulk. In these three regions, the crop is taken to the car either 
loose in wagon boxes, or in bags, or both ways, with the bags piled on top 
of the load. 



1268 



Earle V. Hardenburg 




Pig. 152. the bushel hampers commonly used for both picking up and hauling to 

market in nassau county 




Fig. 153. a Nassau county road wagon, loaded for the wallabout markets of Brooklyn 



A Study of Factors Influencing the Yield of Potatoes 1269 

TYPES of storage IN THE FOUR REGIONS SURVEYED 

Since Appleman (1912) has shown the importance of low temperature 
in proper potato storage, it is of interest to note the types of storage used for 
the crops concerned in these studies. In no case was any grower's crop 
kept in a refrigerated storage. The proportion of the total stored crop in 
each region which was stored in various types of storage facihties is given 
in table 92. The reason for the larger number of farms indicated in Steuben 

TABLE 92. Types of Potato Storage in the Four Regions Surveyed 



Region 


Number 

larms 


Per cent of stored crop stored in 


House 
cellar 


Barn 
cellar 


Special 
storage 


B'arn 
shed 


Pit 
storage 


Long Island, 1912 . . 


231 

378 
320 

300 


61 

85 

72 

98 


22 
11 
24 

1 


12 
3 
3 

1 


3 






9 


Steuben County, 1912 

Monroe Comity 1913 


1 


Franklin and Clinton Counties, 
1913 










and Monroe Counties than were actually visited in the survey, is due to 
the fact that a number of the growers in these regions stored their crop in 
more than one type of storage. 

Practically all of the Franklin and Clinton County crop of 1913 was stored 
in the house cellar. In fact, this was the principal type of storage, tho 
to a lesser extent, in the other regions studied. The next most popular 
type of storage was the barn cellar. As a rule, both house and barn 
cellars were constructed with stone walls and dirt floors. Wherever a barn 
cellar was used, it was generally in close proximity to the stable, advantage 
being thus taken of the animal heat therefrom to prevent freezing. This 
was not considered a safe practice in Franklin and Clinton Counties because 
of the greater severity of the winters in that region. A number of special 
storage houses were found on Long Island. Since only a small proportion 
of the Long Island crop is held for more than a few days, these special 
storages were built not so much to store the harvested crop as for a place 
of storage for the seed supply brought in from the North to be held until 
planting time. 



LENGTH OF STORAGE PERIOD 

In determining the length of time that the crop was held by the growers 
in each region, the actual date of sale of all or of parts of the crop was taken 
as an indicator of the storage period. It was found that a large part of 
the crop in all four regions was marketed either directly from the field, or 



1270 



Earle V. Hardenburg 



after only a few days of holding for proper grading and bagging at the 
barn. In table 93, the proportion of the crop so handled is considered as 
not stored. 

TABLE 93. Length of Storage Period in the Four Regions Surveyed 











Per cent of crop stored 






Region 




For 


For 


For 


For 


For 


For 


For 




None 


one 


two 


three 


four 


five 


SIX 


seven 






month 


months 


months 


months 


months 


months 


months 


LoiiR Island, 1912. 


88 


5 





3 


2 


1 





1 


Steuben County, 


















1912 


64 


6 


12 


6 


8 


3 


1 





Monroe County, 


















1913 


38 


3 


11 


21 


11 


10 


5 


1 


Franklin and Clin- 


















ton Counties, 


















1913 


42 


1 


12 


21 


17 


1 


5 


1 







As is indicated in table 93, a larger proportion of the crop is stored for 
one or more months in the three regions of western and northern New York 
than on Long Island. Except on Long Island, the general practice is to 
market at least that part of the crop for which there is insufficient storage 
capacity, at harvest time, the remainder being disposed of as prices warrant 
and as weather and country roads perm.it. Much of the crop in Steuben 
County is grown under contract for local buyers. The grower's delivery 
of this crop mainly at harvest time accounts for the relatively high propor- 
tion of the crop not stored in this region. 

SUMMARY 

Climate, elevation, and soil, as factors influencing yield, were found by 
this study to be so closely and inseparably related as to make difficult the 
determination of the influence of each one. The study of available data 
shows that, whereas the climate for potatoes is generally best at the 
highest elevations, soil fertility is generally the greatest at the lower eleva- 
tions. In a year of blight, farms at high elevations are likely to show the 
best yields ; while in years of no blight, better yields may be expected from 
the more fertile soils at the lower elevations. 

The value of potato land as appraised by the growers, proved to be corre- 
lated with yield up to the point at which the land was affected by real -estate 
valuation. This point was reached for a few farms located in close proxim- 
ity to cities or villages. The appraised valuation of these farms was 
evidently beyond the valuation justified by their productive ability. 



A Study of Factors Influencing the Yield of Potatoes 1271 

From information obtained in the survey of the four regions, it has been 
possible to determine the status of many factors which, tho not studied as 
to their influence on yield, have nevertheless a vital relation to production. 
Among these may be listed the time of plowing, the home-mixing of 
fertilizer, the analysis of fertilizer, the use of lime, the source of seed, the 
chemical treatment of seed, the date of planting, the method of planting, 
the date and method of harvesting, the type of storage, and the length of 
the storage period. 

Both biometrical and tabulation studies have shown the amount of seed 
used and the value of manure and fertilizer per acre to be the most influen- 
tial factors as relating to yield of all the factors studied. Second to these 
are depth of plowing, frequency of cultivation, and frequency of spraying. 
The influence of these five factors, expressed biometrically in terms of r, 
is summarized for each region in table 94. For obvious reasons, based 



TABLE 94. Summary of Coefficients of Correlation for Five Factors in the 
Regions Surveyed 



Depth of plowing 

Value of manure 
and fertilizer.. . 

Bushels of seed 
used 

Frequency of cul- 
tivation 

Frequency of bor- 
deaux spraying. 



Long Island, 
1912 



r = 0.159 ± 0.036 
r = 0.244 ± 0.035 
r = 0.275 ± 0.034 
r = -0.087 ± 0.037 
r = 0.133 ± 0.065 



Steuben County, 
1912 



: 0.190 ± 0.034 
■■ 0.289 ± 033 
: 0.374 ± 0.031 
'■ 0.231 ± 0.034 



Monroe County, 
1913 



r = 0.006 ± 0.039 
r = 0,258 ± 0.033 
r = 0.247 ± 0.037 
r = 0.169 ± 0.038 
r = 0.084 ± O.OSl 



Franklin and 

Clinton Counties, 

1913 



r = 0.028 ± 0.039 
r = 0.169 ± 0.038 
r = 0.387 ± 0.034 
r = 0.055 rt 0.039 



chiefly on environmental differences between the four regions, consider- 
able variation in the value of coefficients is shown in the table. In a single 
case, that for frequency of cultivation on Long Island, the coefficient' is 
negative. Five coefficients out of the eighteen given are too small to be 
significant, the probable reasons for this being, in most cases, explained in 
the foregoing text. In but two cases is the probable error greater than 
the coefficient, these being the probable errors of the coefficients for depth 
of plowing in Monroe County and in Franklin and Clinton Counties. 

Probably a more reliable measure of the true influence of these five 
factors on yield may be obtained from the tabulation studies for ea^h 
region. In view of the proved importance of these factors, a compari- 
son of the averages of some of them for the fifty highest- and the fifty 
lowest-yielding farms in the four regions is given in table 95. In general, 
the values given in this table confirm the results shown in the discussion 
of these factors. 



1272 



Earle V. Hardenburg 



TABLE 95. Comparison of Fifty Highest- and Fifty Lowest- Yielding Farms of the 
Four Regions Surveyed, in Average Yield, Potato Acreage, Seed Used, and 
Fertilizer Used, and Percentage of Growers Spraying with Fungicide 



Region 


Average 

yield 
per acre 
(bushels) 


Average 
potato 
acreage 
per farm 


Average 
amount of 
seed used 
per acre 
(bushels) 


Average 

value of 

manure and 

fertilizer 


Per cent of 
growers 
spraj'ing 

with 
fungicide 




High- 
est 


Low- 
est 


High- 
est 


Low- 
est 


High- 
est 


Low- 
est 


High- 
est 


Low- 
est 


High- 
est 


Low- 
est 


Long Island, 1912. . 
Steuben County, 
1912 


254.6 
204.6 
205.1 

247.8 


95.6 
72.4 
64.0 

114.8 


29.8 
15.1 
13.2 

7.0 


18.2 
12.0 

12.8 

7.5 


13.6 
11.2 
13.6 

13.6 


11.6 
9.0 
11.7 

10.7 


$35.35 
13.65 
14.12 

15.09 


$29.56 
7.78 
9.08 

11.78 


50 
16 
20 




16 



Monroe Count y, 
1913 


22 


Franklin and Clin- 
t n Counties, 
1913 


2 







Factors of less, but by no means negligible, influence on yield, as 
developed by these survey studies, are: method of applying fertilizer, 
varietal type of potatoes, sun-sprouting of seed, interval between cutting 
seed and planting, dusting cut seed, type of seed, system of planting, 
depth of planting, system of cultivation. 

CONCLUSIONS 

The foregoing study of crop production by survey methods has, wholly 
apart from the facts brought out, shown the broad possibilities of this 
method of research. It does have limitations, however, as is evidenced 
by certain conflicting data and by the occasionally inconclusive results 
reported herein. It cannot be used as a substitute either for the present 
carefully executed research of the state and federal experiment stations, 
or for more generally localized controlled experiments. On the basis of 
faets and indications revealed in this study, however, the survey method 
can and should play a more prominent part in supplementing the present 
scope of research. In general, too much emphasis has been placed on 
conclusions drawn from limited experimentation without due attention 
to their application to local concUtions. Too little research of regional 
application has been done. Cooperative experiments have been tried, 
but they have not been sufficiently extensive in duration. 

A crop survey, to be of greatest value, should be replicated in a given 
region, depending on the normality of seasonal conditions. The year 
1912, while possibly normal for Long Island, was a year of severe loss 
from blight to the potato crop in Steuben County. The year 1913, while 
possibly normal for Franklin and Clinton Counties, was a year with an 
extraordinarily early killing fall frost in Monroe County. These factors 
have doubtless vitiated to some degree the results of the present study 



A Study of Factors Influencing the Yield of Potatoes 1273 

of the influence of certain factors on yield. A larger number of records 
for each region, and replication of the survey, may be suggested as the 
best and probably the only means of obviating these conditions. Whereas 
sufficient records were not available for the detailed study of some factors, 
the number used has, on the whole, afforded means for fairly definite 
conclusions. For as extensive a study of details as has been pursued in 
the present investigations, not less than three hundred, and preferably 
four hundred, records should be used. Aside from the relative influence 
of various factors on yield as revealed in these studies, it has been possible 
to correct, as well as to verify, many popular ideas of long standing. Altho 
the " what," the " why," and the " how " of crop production have for 
years been projected to the farmer, the regional study of actual cause 
and effect by survey methods has at least contributed to the knowledge 
as to the " how much." 

AUTHOR'S ACKNOWLEDGMENT 

The writer wishes to make acknowledgment of the help given him by 
Professor E. G. Montgomery, under whose direction this investigation 
was made, and to express appreciation to Messrs. D. S. Fox, W. M. 
Peacock, M. F. Abell, R. F. Pollard, and R. H. Cross, who assisted in the 
taking of records. Grateful acknowledgment is made also to the many 
farmers who furnished the information necessary, and to Miss Nellie Van 
Dyne for her capable assistance in the compilation of the data. 



1274 Earle V. Hardenburg 



BIBLIOGRAPHY 

Adams, L. H. Potatoes. In Report on wheat, oats, barley, corn, and 
potatoes, for 1887. Wisconsin Agr. Exp. Sta. Bill. 13:8-16. 1887. 

Report on potatoes for 1889. In Report on oats, barley. 



and potatoes for 1889. Wisconsin Agr. Exp. Sta. Bui. 22: 7-12. 1889. 

AicHER, L. C. Whole vs. cut potato tubers for planting on irrigated land. 
Amer. Soc. Agron. Journ. 9:217-223. 1917. 

App, Frank. Farm profits and factors influencing farm profits on 370 
potato farms in Monmouth County, New Jersey. New Jersey Agr. 
Exp. Sta. BuL 294:1-103. 1916. 

Appleman, Charles O. Changes in potatoes during storage. Mary- 
land Agr. Exp. Sta. Bui. 167:327-334. 1912. 



Biochemical and physiological study of the rest period in 

the tubers of Solamim tuberosum. Maryland Agr. Exp. Sta. Bui. 
183:181-226. 1914. 

Physiological basis for the preparation of potatoes for seed. 



Maryland Agr. Exp. Sta. Bui. 212:79-102. 1918. 

Arthur, J. C. The potato: relation of the number of eyes qn the seed 
tuber to the product. Purdue Univ. (Indiana) Agr. Exp. Sta. Bui. 
42:103-118. 1892. 

Ba'lentine, Walter. Investigation on the foraging powers of some 
agricultural plants for phosphoric acid. Maine Agr. Exp. Sta. Ann. 
rept. 1893:13-25. 1894. 

Ballou, F. H. The status of the potato growing industry in Ohio. In 
Ohio Agr. Exp. Sta., Bui. 218:561-595. 1910. 

Brooks, William P. Fertilizers for potatoes. Massachusetts Agr. Exp. 
Sta. Circ. 42. 1914. 

Champlin, Manley, and Winright, George. Potato culture in South 
Dakota. South Dakota Agr. Exp. Sta. Bui. 176:694-764. 1917. 

Clement, P. E., and Werner, H. O. Potato culture in North Dakota. 
North Dakota Agr. Exp. Sta. Ext. bul. 10:1-12. 1917. 

Clinton, G. P. Potato spraying experiments, third report. Connecti- 
cut Agr. Exp. Sta. Rept. 39 (1915):470-487. 1916. 



A Study of Factors Influencing the Yield of Potatoes 1275 

Conner, Chas. M. A preliiuinarv- report on growing Irish potatoes. 
Florida Agr. Exp. Sta. Bui. 82:391-406. 1906. 

CuMMiNGS, M. B.' Apple orchard survey of Niagara Count3% Cornell 
Univ. Agr. Exp. Sta. Bui. 262:277-320. 1909. 

Dickens. Albert. Potato culture. Kansas Agr. Exp. Sta. Bui. 194: 
473-491. 1914. 

Emerson, R-. A. Potato experiments. Nebraska Agr. Exp. Sta. Bui. 
97:1-26. 1907. 

'Home mulched vs. northern seed potatoes for eastern 

Nebraska. Nebraska Agr. Exp. Sta. Bui. 146:1-36. 1914. 

Flagg, Charles O., Towar, J. D., and Tucker, George M. Experi- 
ment with seed tubers budded and not budded. Rhode Island Agr. 
Exp. Sta. Bui. 36:16-19. 1896. 

Fox, D. S. A farm crops survey in New York, with especial reference 
to potato production. Thesis for degree of Ph. D., Cornell University. 
(Unpubhshed.) 1916. 

An analysis of the costs of growing potatoes. Cornell Univ. 

Agr. Exp. Sta. Mem. 22:525-627. 1919. 

Eraser, Samuel. The potato, p. 1-185. 1912. 

Geismar, Leo M. Report of the Upper Peninsula sub-station foi; the 
year 1904. In Forty-fourth annual report of the Secretary of the State 
Board of Agriculture of the State of Michigan, and eighteenth annual 
report of the Experiment Station from July 1, 1904, to June 30, 1905. 
Michigan Agr. Exp. Sta. Sp. bul. 31:483-509. (Reference on p. 493- 
496.) 1905. 

GouRLEY, Joseph H. Seasonal report on potatoes, 1909. In Ohio Agr. 
Exp. Sta., Bul. 218:597-603. 1910. 

Green, W. J. Experiments with potatoes. In Report of the horti- 
culturist. Ohio Agr. Exp. Sta. Rept. 6:196-210. 1887. 



Potatoes. Ohio Agr. Exp. Sta. Rept. 7:116-127. 

Hall, A. D. Experiments on the continuous growth of potatoes on the 
same land, Hoos Field, 1876-1901. In The book of the Rothamsted 
experiments, p. 122-127. 1905. 

Hardenburg, E. V. Potato machinery efficiency as applied to produc- 
tion in Steuben County. Thesis for degree of M. S. in Agr., Cornell 
University. (Unpublished.) 1915 a. 



1276 Earle V. Hardenburg 



Factors influencing potato production in Steuben County 

studied by the survey method. Thesis for degree of M. S. in Agr., 
Cornell University. (Unpublished.). 1915 b. 

Report of potato inspection work in 1917. New York State 



Potato Assn. Proc. 4:5-9. 19i: 

Hartwell, Burt L., and Damon, S. C. A twenty-year comparison of 
different rotations of corn, potatoes, rye, and grass. Rhode Island 
Agr. Exp. Sta. Bui. 167:1-38.- 1916. 

Harwood, p. M. Potatoes. Michigan Agr. Exp. Sta. Bui. 95:1-20. 
1893. 

Harwood, P. M., and Holden, P. G. Potatoes. Amounts of seed. 
Michigan Agr. Exp. Sta. Bui. 93:1-53. 1893. 

Hume, A. N., Champlin, Manley, and Oakland, I. S. Selection and 
preparation of seed potatoes — size of seed piece and bud variation. 
South Dakota Agr. Exp. Sta. Bui. 155:97-112. 1914. 

HuTCHESON, T. B., and Wolfe, T. K. Potato culture. Virginia Agr. 
Exp. Sta. Bui. 217:1-16. 1917. 

Johnson, Samuel. Potato culture. — Varieties. — Experiments with dif- 
ferent amounts of seed. Michigan Agr. Col. Bui. 13:1-8. 1886. 

Experiments with potatoes and oats. Michigan Agr. Col. 

Bui. 34:1-8. 1888. 

Johnson, T. C. Truck crop potatoes. Virginia Truck Exp. Sta. Bui. 
7:131-154. 1912. 

Truck crop potato fertilizers. Virginia Truck Exp. Sta. 

Bui. 21:431-452. 1916. 

Jones, L. R. Certain potato diseases and their remedies. Vermont 
Agr: Exp. Sta. Bui. 72:1-32. 1899. 

Jordan, W. H. Commercial fertilizers for potatoes. New York (Geneva) 
Agr. Exp. Sta. Bui. 187:215-232. 1900. 

Jordan, W. H., and Sirrine, F. A. Potato fertihzers: method of applica-" 
tion and form of nitrogen. New York (Geneva) Agr. Exp. Sta. Bui. 
327:283-304. 1910. 

KoHLER, A. R. Potato experiments and studies at Univcrsitv Farm. In 
Univ. Minnesota Agr. Exp. Sta., Bui. 114:289-333. 1909. " 

Potato experiments and studies at University Farm in 1909. 



Univ. Minnesota Agr. Exp. Sta. Bui. 118:65-141. 1910. 



A Study of Factors Influencing the Yield of Potatoes 1277 

LuTMAN, B. F. Plant diseases. Twenty * years' spraying for potato 
diseases. Potato diseases and the weather. Vermont Agr. Exp. Sta. 
Bui. 159:213-296. 1911. 

McMuRRAN, S. M. Pecan rosette in relation to soil deficiencies. U. S. 
Agr. Dept. Bui. 756:1-11. 1919. 

Macoun, W. T. The potato and its culture. Cent. Exp. Farm, Canada 
Agr. Dept. Bui. 49:1-48. 1905. 

Martin, H. M. An apple orchard survey of Ontario County. Cornell 
Univ. Agr. Exp. Sta. Bui. 307:161-215. 1911. 

Montgomery, E. G. Farm crop surveys. Amer. Soc. Agron. Journ. 
5:232-233. 1913. 

MuNSON, W. M. Notes of potatoes. In Report of th§ horticulturist. 
Maine Agr. Exp. Sta. Ann. rept. 1893:121-124. 1894. 

Plumb, C. S. Experiments in growing potatoes. Tennessee Agr. Exp. 
Sta. Bui. 3^:1-24. 1890. 

Rane, F. William, and Hall, H, F. Ten experiments with potatoes 
and potato culture for New England. New Hampshire Agr. Exp. 
Sta. Bui. 111:107-130. 1904. 

Rane, F. William, and Hunt, Leigh. Potatoes. New Hampshire 
Agr. Exp. Sta. Bui. 41 : 1-14. , 1897. 

Rietz, Henry L., and Smith, Louie H. On the measurement of cor- 
relation with special reference to some characters of Indian corn. Illinois 
Agr. Exp. Sta. Bui. 148:291-316. 1910. 

Sandsten, E. p., and Delw^iche, E. J. Potato culture in northern Wis- 
consin. Wisconsin Agr. Exp. Sta. Bui. 177:1-17. 1909. 

Sandsten, E. P., and Milward, J. G. The spraying of potatoes for pre- 
vention of leaf bhght and rot. Wisconsin Agr. Exp. Sta. Bui. 135: 
1-24. 1906. 

Schw^eitzer, p. Enquiry into the principles of potato growing, and 
tests of varieties. Missouri Agr. Exp. Sta. Bui. 33 : 1-24. 1896. 

Shepperd, J. H., AND Churchill, 0. 0. Potato culture. North Dakota 
Agr. Exp. Sta. Bui. 90:81-126. 1911. 

Smith, J. Warren. The effect of weather upon the yield of potatoes. 
Monthly weather rev. 43 : 222-236. 1915. 

Spillman, W. J. Validitv of the survey method of research. U. S. Agr. 
Dept. Bui. 529:1-15. 1917. 



1278 Earle V. Hardenburg 

Stewart, F. C, French, G. T., and Sirrine, F. A. Potato spraying 
experiments, 1902-1911. New York (Geneva) Agr. Exp. Sta. Bui. 
349:99-139. 1912. 

Stone, J. L. Potato growing in New York. Cornell Univ. Agr. Exp. 
Sta. Bui. 228:425-450. 1905. 

Stuart, William. Place-effect influence on seed potatoes. Vermont 
Agr. Exp. Sta. Bui. 172:197-216. 1913 a. 

Good seed potatoes and how to produce them, U. S. Agr. 

Dept. Farmers' bul. 533:1-16. 1913 b. 

Group classification and varietal descriptions of some Ameri- 
can potatoes. U. S. Agr. Dept. Bul. 176:1-56. 1915. 

Taft, L. R. Potato tests. Michigan Agr. Exp. Sta. Bul. 85:1-21. 
1892. 

Taft, L. R., and Coryell, R. J. Potatoes and the potato scab. Michi- 
gan Agr. Exp. Sta. Bul. 108:29^7. 1894. 

Thompson, A. L. Cost of producing milk on 174 farms in Delaware 
County, New York. Cornell Univ. Agr. Exp. Sta. Bul. 364:109-179. 
1915. 

ToLLEY, H. R. The theory of correlation as applied to farm-survey data 
on fattening baby beef. U. S. Agr. Dept. Bul. 504:1-14. 1917. 

Van Slyke, L^ L. Comparative field-test of commercial fertilizers used 
in raising potatoes. New York (Geneva) Agr. Exp. Sta. Bul. 93(n.s.) : 
262-278. 1895. 

Warren, G. F. The apple industry of Wayne County, New York. 
Cornell Univ. Agr. Exp. Sta. Bul. 226:227-362. 1905 a. 

An apple orchard survey of Orleans County. Cornell Univ. 

Agr. Exp. Sta. Bul. 229:457-499. 1905 b. 

Agricultural surveys. Cornell Univ. Agr. Exp. Sta. Bul. 



344:417-433. 1914. 

Warren, G. F., and Livermore, K. C. An agricultural survey: town- 
ships of Ithaca, Dryden, Danby, and Lansing, Tompkins County, New 
York. Cornell Univ. Agr. Exp. Sta. Bul. 295:375-569. 1911. 

Welch, John S. Whole vs. cut potato tubers for planting on irrigated 
land. Amer. Soc. Agron. Journ. 9:224-230. 1917. 

Wheeler, H. J., and Adams, G. E. Further results in a rotation of 
potatoes, rye, and clover. Rhode Island Agr. Exp. Sta. Bul. 135: 
99-126. 1909. 



A Study of Factors Influencing the Yield of Potatoes 1279 

Wheeler, H. J., To war, J. D., and Tucker, G. M. The effect of liming 
upon the development of potato tubers. In Fertilizers. Potatoes. 
Potato scab. Rhode Island Agr. Exp. Sta. Bui. 33 : 46-50. 1895. 

Whipple, 0. B. Thinning experiments with potatoes. Montana Agr. 
Exp. Sta. Bui. 106:1-8. 1915. 

Whitney, Milton. FertiHzers for potato soils. U. S. Soils Bur. Bui. 
65:1-19. 1910. 

Woods, Charles D. Field experiments. Maine Agr. Exp. Sta. Bui. 
188:25-32. 1911. 

Field experiments. Maine Agr. Exp. Sta. Bui. 224:25-48. 



1914. 



Barn and field experiments in 1916. Maine- Agr. Exp. Sta. 



Bui. 260:85-120. 1917. 

Barn and field experiments in 1917. Maine Agr. Exp. Sta. 

Bui. 269:1-44. 1918. 

Woods, Charles D., and Bartlett, J. M. Field experiments in 1906-8. 
Maine Agr. Exp. Sta. Bui. 167:85-104. 1909. 

Zavitz, C. A. Potatoes. Ontario Agr. Dept. Bui. 239:1-88. 1916. 



Memoir 52, Studies in Pollen, with Special Reference to Longevity, the fifth pieced'ns number in this series 
of publications, was mailed on March 9, 1922. 



NEW YORK STATE COLLEGE OF AGRICULTURE 

CORNELL UNIVERSITY, ITHACA, N. Y. 

DEPARTMENT OF FARM PRACTICE AND FARM CROPS 



Farm No 


Potato Record for 1912. Date . 




Operator 


Age 


P. O County 


Location 


Miles to shipping point 


Soil types Elevation 




Drainage 


Exposure 191 


Acres farmed 


Value of land per acre 


Acres potatoes 4912 


Tenure 


Years owner . 


Years renter 


Rotation 1 


:2 3 4 


5 6 



CROP PRODUCTION FOR 1912 



Crop 



Corn, grain 

Corn, silage 

Com, other 

Wheat 

Rye 

Oats 

Barley 

Buckwheat 

Hay 

Alfalfa 

Oat Hay 
Oats and Barley 
Oats-and Peas 
Field Beans 
Cabbage 
Cauliflower 
Brussels Sprouts - 
Apples Bearing 
Apples not Bearing 



crates 
bu 



POTATO PRODUCTION FOR 1911, 1912 AND 1913. 



Year 


Varieties 


Acres 


Yield per acre 


Total yield 


Early 










1911 










Late 










ToUl 










Early 










1912 










Late 




. 






ToUl 











Early 

1913 

Late 














::::;::::::... 











-™.^ - 











-■ — _ 


Tout 








,t.., ^ 



DISPOSAL OF 1912 CROP 





Dale 


BushelB 


Price per bn. 


Total 


Sold 





















Seed 






Feed 










Home use 













































SPECIAL EQUIPMENT 






C<l8t 


Value 1912 


Life 


DepredaUon 


Cost of repairs 




...$ 






....$ 


..-^5 >: 










Digger 


:::::::: 








Cutter 

Other equip 

Total ,. 




z' ziiz'i. 






EXPENSES 1912 





Amount Price per unit 


Total 


RenUl value of land 


acres 


.$ 






tons 







Manure from preceding crop 


tons.... 




Manure, used by 1912 crop 


tons.... 






Seed, farm and bought 


bu 






lbs 

lbs 




Copper sulphate 




Lime (form for spray) 


.lbs 




Insecticide (kind) 


lbs 










Equipment Rented 












Repairs on machinery 








Depreciation on machinery 








Man labor 


hrs. 






Horse labor 


hrs. . 






Equipment labor 


hrs. 










Total 





SUMMARY 
Total receipts S 

Total expenses S 

Profit 1912 crop S 

Profit per acre $ . 



LABOR ITEMS 





Date 


Acres 


Per 


acre ToUl 












1 












Plowing, Fall 






















1 




i 


Rolling, times 












1 


• 




Removing sprouts, times 

Starting sprouts 




' 




Marking - 

Planting, machine _ 

Planting, hand 

Fertilizer 
































Hilling, times 







.::::: 




Spraying, times 

Digging and picking up, (hand) i 




Harrowing after digging : 








Hauling to storage 
Hauling to market ... 
Hauling from storage to market 

Work on equipment 

Work on storage 


Total 

















■MISCELLANEOUS FACTORS 



Manure. Kind used Tons per acre 

Where applied Name of spreader, 

often in rotation Piled or spread 

Value of residual manure on potatoes, 1912 per cent 

Plowing. Depth of plowing 

Seed. Source Amt. used 

Seed Treatment. Corrosive sublimate. Formalin. Formaldehyde gas. Flow 

,. How treated 

Satisfactory? Consequent injury to vitality ? 

Starting Sprouts. Increase in yield noted 

Cutting Seed. Amt. cut Name of the 

Satisfactory ? Type of seed planted : 

1. Small whole 

2. Medium whole 

3. Large cut, 3 or 4 pieces . 

4. Medium cut, 2 or 3 piece? 

5. No. eyes to piece 



Source, it bought 

used 

Plowed in or harrowed 



; of sulphur. Formula 



Increased earliness noted 



How long cut before planted 
Fertilizer. Amt. per acre 
Source of N 
Home mixed 



Formula 
Source of P 
Ingredients used 



Cut seed dusted 
Brand 

Source of K 
Amt. 





r used 








Insecticide used 




Amount used 



Time of application 
Above, with or below seed 
Place and frequency in rotation 

Planting. Date, Early 

planter 

How covered Depth planted 

Coltivating. Type of cultivator 
No. times in row at each cultivation 

Hilling. Checkrowing, ridging or level culture 
'.. Typ 
xd 

ised . 
Spray injury noted ? 
Yield on unsprayed 

Digging. How dug 
What kind would you buy 

Sorting. Sorted directly 
Times 

Bagging or Barreling. Type of carrier used 

Marketing. Commission rates 
Shipping rates 

Storage. Type of storage . 

Diseases Evident. 
Effect of manure or lime on diseases 

Labor. 

Wages per month 

Wages per month and board 

Wages per day and board 

Work done by women and children 



Jiills, broadcast, fert. drill, planter, 
Amt. lime per acr 



Late , "12. By hand 

What kind would you buy 

Distance apart of rows . 



planter ? Type of 

Marker used 

rows Distance apart in ro«s 

Deep or shallow 
Cultivated both ways or one 



Increased yield noted 
Date of first spraying 
Name of digger 

boxes, sorting table, or sort* 
- Reason 



Id on sprayed 

Last spraying, 

-Type of digger 



Capacity 
System of marketing 

Where shipped , , 

Description of storage 



Wages per day 

..Board 



FACTORS ON 1912 COST OF PRODUCTION 



Total acreage 

Crop acres 

Per cent in crops 

Acres in potatoes 

Per cent of crop acres in potatoes 

Value of land per acre 

Rental value of land per acre 

Crop index 

Value of potato crop per acre 

Potato crop index 

Total potato production, 1912 
Average yield per acre 
Total man hours per acre 
Total horse hours per acre 

Cost of fertilizer per acre 
Cost of manure per acre 
Cost of cultivation per acre 
Cost of spraying per acre , 

Cost of digging per acre 

Cost of special equip, per acre 



Cost per bu 

Receipts per acre 

Cost per acre 
Profit per acre 
Profit per man hour 
Profit per horse hour 
Profit per bushel 



Per cen 


of 


Percen 


of 


Per cen 


of 


Per cen 


of 


Per cen 


of 


Per cen 


of 


Percen 


of 


Per cen 


of 


Percen 


of 



cost, man labor 
cost, horse labor 
cost, land labor 
cost, manuring 
cost, fertilizing , 
cost, cultivation 

cost, spraying 
cost, digging 
cost, special equip. 



LIBRftRY OF CONGRESS 



IIM 



002 685 241 9 • 



